I now better appreciate Prof. Noakes' reasons for using the words he
used following his response to my eletter posted on the BJSM Blog, and
consider the issue of "data exclusion" settled. However, I would like to
make the following points to clarify my position and respond to Noakes'
interpretation of the physiology:
1. I do not consider myself "wedded to the Hill model" because the
"Hi...
I now better appreciate Prof. Noakes' reasons for using the words he
used following his response to my eletter posted on the BJSM Blog, and
consider the issue of "data exclusion" settled. However, I would like to
make the following points to clarify my position and respond to Noakes'
interpretation of the physiology:
1. I do not consider myself "wedded to the Hill model" because the
"Hill model" as presented by Noakes bears no relationship to my
understanding of the physiological response to exercise. It is my
contention that the "Hill model" is an erroneous caricature of the
physiology of exercise that Noakes uses as a straw man in contrast to his
central governor model. Few scientists are likely to defend the view that
cardiac output and VO2 must always be identical at exhaustion, for the
evidence against this proposition is overwhelming! In short, the “Hill
model” is not a contemporary model of exercise physiology, it is a vehicle
invented by Noakes.
2. “Oxygen consumption" or, more correctly, pulmonary oxygen uptake,
is not a "surrogate measure of cardiac output and the state of muscle
oxygenation". To claim this indicates a misunderstanding or
misrepresentation of basic physiological measurements. Pulmonary VO2 is
useful because in both the non-steady state and the steady state it
closely reflects muscle VO2, which itself reflects energetic events
occurring in the cell. If one accepts that the rate of energy transfer is
an important consideration during exercise, then measuring the most
quantitatively significant energy transfer process is worthwhile.
Furthermore, the phrase “state of muscle oxygenation” is hopelessly vague.
Does Noakes mean “muscle O2 extraction”, “arterio-venous oxygen
difference” or “intracellular [or mitochondrial] PO2”? The first two
measures are difficult to make, whilst the latter is currently impossible
to make during whole-body exercise.
3. I do not “believe” that exhaustion occurs before VO2max is
attained during "extreme" exercise, it is an experimental fact: exercise
is terminated whilst VO2 is still rising in a futile attempt to meet the
energetic demand.[1] Exercise under these conditions is terminated
because the subject is no longer able to sustain the power requirements of
the task (in my experience not because the subject is unwilling), but this
says little of the mechanism. Classic works on the aetiology of muscle
fatigue acknowledge that fatigue processes occur at a number of sites
within the neuromuscular system,[2,3] and I certainly embrace this.
Exhaustion at these “extreme” work rates is attended by falling [PCr] and
pH and rising [Pi] and [ADP], amongst other derangements known to cause a
fall in tension produced by the myocyte.[4] However, measurements of
these processes in whole-body exercise are presently too spatially or
temporally crude to be definitive – but that is certainly not a reason to
reject the periphery as a plausible or even pivotal contributor to task
failure (exhaustion). Note also that the identification of metabolites
involved in substrate-level phosphorylation does not imply that the
conditions within the cell are “anaerobic”: the concentrations of these
metabolites will change progressively during exercise above the so-called
“critical power”[5] irrespective of cellular PO2.[6]
4. Noakes argues that the “simulaneous [sic] measurement of muscle
activation” is required to test the alternate (central governor) theory
“that maximal exercise always terminates before there is 100% activation
of all the available motor units in the exercising limbs”. However, this
is impossible to verify with current technology. Even if
electromyographic recordings are taken from the surface of a large number
of muscles and normalised to some measure of maximal voluntary muscle
function (such as an MVC), this will not provide an estimate of the
fractional number of motor units that are active. The EMG signal is
determined, in part, by the number of active muscle fibres in the region
of interrogation, their firing frequency, and the conductivity of the
tissues between the fibres and the electrodes, not simply by the number of
active motor units. A method of determining the total number of active
motor units during whole-body exercise would be very useful but does not
currently exist.
The processes leading to additional motor unit recruitment during
rhythmic whole-body exercise are far from understood. However, it is
logical that in conditions where the rate of O2 delivery is maximal (i.e.,
when cardiac output is maximal) the recruitment of additional motor units
will lead to worsening metabolic conditions within the exercising muscles,
as those newly recruited fibres will also extract O2 from the
microvasculature. The consequent fall in microvascular PO2 will make the
appropriate matching of O2 demand and supply (essential for the
continuance of exercise) increasingly difficult. Additional motor unit
recruitment is thus likely to yield diminishing returns in terms of
sustaining the required power output. In this scenario, task failure will
occur before all motor units are activated even in the absence of a
“governor”.
In summary, Prof. Noakes’ representation of the physiology of
exercise could be charitably described as inaccurate. The “Hill model” is
not one that any physiologist is “wedded” to because it does not exist.
Therein lay the “misleading interpretations” to which I referred in my
first letter. One final point needs to be made:
If the “absence of any such catastrophe [myocardial ischaemia or
rigor during exercise] suggests the presence of an anticipatory, complex,
regulatory control system”[7], then surely the presence of myocardial
ischaemia during exercise[8] suggests the absence of an anticipatory,
complex regulatory control system? How long can the central governor
theory survive with this elephant in the room?
“It does not make any difference how beautiful your guess is. It does
not make any difference how smart you are, who made the guess, or what his
name is - if it disagrees with experiment it’s wrong. That’s all there is
to it.” Richard P. Feynman.
References
1. Hill DW, Poole DC, Stevens JC. The relationship between power and
the time to achieve VO2max. Med Sci Sports Exerc. 2002;34:709-714
2. Bigland-Ritchie B, Woods JJ. Changes in muscle contractile
properties and neural control during human muscular fatigue. Muscle Nerve.
1984;7:691-699.
3. Gandevia SC. Spinal and supraspinal factors in human muscle
fatigue. Physiol Rev. 2001;81:1725-1789.
4. Fitts RH. The cross-bridge cycle and skeletal muscle fatigue. J
Appl Physiol. 2008;104:551-558.
5. Jones AM, Wilkerson DP, DiMenna F, Fulford J, Poole DC. Muscle
metabolic responses to exercise above and below the “critical power”
assessed using 31-PMRS. Am J Physiol Regul Integr Comp Physiol.
2008;294:R585-R593.
7. Noakes TD. Peer review/fair review: How did A.V. Hill understand
the VO2max and the “plateau phenomenon”? Still no clarity? Brit J Sports
Med, in press. DOI: 10.1136/bjsm.2008.046771.
8. Bogaty P, Poirier P, Boyer L, Jobin J, Dagenais GR. What induces
the warm-up ischemia/angina phenomenon: exercise or myocardial ischemia?
Circulation. 2003;107:1858-1863.
In their paper [1], McDowell and Ciocco conclude that "BBS values in slowpitch softball exceed recommended safety limits imposed on the sport" and their "findings indicate that softball is perhaps more dangerous then most coaches, players and parents think." Had this paper been published in an American journal it might have attracted considerable attention from the news media due to its alarming conclusion...
In their paper [1], McDowell and Ciocco conclude that "BBS values in slowpitch softball exceed recommended safety limits imposed on the sport" and their "findings indicate that softball is perhaps more dangerous then most coaches, players and parents think." Had this paper been published in an American journal it might have attracted considerable attention from the news media due to its alarming conclusions. However, it is also possible that if this paper had been submitted to an American journal, reviewers more familiar with the current status of performance testing in softball might have identified some fatal flaws.
Had this paper been published five years ago, the conclusions drawn would have been relevant to the game of softball. Unfortunately the performance standards referenced in this study were already out of date, and several of the softball bats tested in this study had already been banned from play by the time this paper was accepted for publication. Furthermore, the references quoted by the authors include television news stories and websites, while ignoring a serious body of recent research on bat performance.
Outdated performance standards. The performance standard used to test softball bats, referenced by McDowell and Ciocco [1], is ASTM F1890. This test specifies that an initially stationary bat is impacted with a ball fired from a cannon at a speed of 26.8 m/s. The ball rebounds from the bat while the bat swings away about a pivot to which the handle is clamped. The ratio of rebounding to initial ball speeds is used to determine the Bat Performance Factor and the Batted-Ball Speed. However, there are two critical flaws in this test, which are completely ignored by McDowell and Ciocco. The first is that the F1890 test standard specifies that the ball must impact the bat at its centre-of-percussion (COP) relative to a pivot point 6-inches (15.24 cm) from the handle end of the bat. Research has shown [2] that the COP is not the location where the ball rebounds from the bat with the greatest speed.
Secondly, several field studies have shown that the relative speed between an actual pitched ball and swung bat in a typical slow-pitch softball game is approximately 49m/s, not 26.8m/s as dictated by F1890. Increasing the speed with which the ball is fired from the cannon causes measured bat performance to increase significantly beyond values obtained by the slower speed F1890 standard.[3-4] Because of both of these reasons, many bats which passed F1890 (BPF or BBS) have been found to perform significantly better in the field than test results predicted.
Sometime around 2002 the ASTM F1890 test standard was revised requiring that location of ball impact be scanned along the barrel in order to determine the bat's actual "sweet spot" before conducting the test, although the ball speed has been kept at 26.8 m/s. The USSSA has been using this modified BPF test for the last couple of years, and several bats which passed the original BPF test have since been banned from USSSA play. In January, 2004, the ASA abandoned the F1890 test altogether and adopted a new bat performance standard, ASTM F2219. This new test fires balls at the higher speed of 49 m/s, and uses the ratio of ball rebound/incoming speeds along with the impact location and the moment-of-inertia to calculate a Batted-Ball Speed representative of what a skilled player in the field would actually produce. The inclusion of the moment-of-inertia is to account for the manner in which the bat-swing speed depends on the inertial properties of the bat [5-7] as found by several recent field tests.
The ASA has set a maximum Batted-Ball Speed limit of 43.8 m/s (157.7 km/h) using the high-speed impact test F2219. While this speed is higher than the 38 m/s (137 km/h) value from the older F1890 test, the current test standard is actually a much more stringent test, is more representative of actually playing conditions, and results in a safer game. Many bats which passed the old F1890 test will not pass the ASA implementation of F2219. Unfortunately, the paper by McDowell and Ciocco does not reflect the recent and current performance standards for testing bat performance.
Illegal and banned bats. A second fatal flaw with this paper is that three of the softball bats which the authors state pose a safety threat to pitchers have long been banned for league and tournament play by both the ASA and USSSA. As a side note, the Miken Velocit-E is not an aluminium multi-wall bat as the authors state, but is in reality a composite bat.
I find it somewhat amazing that the authors included a titanium bat in their study since the Louisville Slugger TPS Titanium bat (along with Worth Titanium and Easton Typhoon Titanium models) was quickly banned by all softball organizations back in 1993, just a few months after it was introduced into the market. Since 1993 (which is 7 years before ASA adopted performance standards) it has always been illegal to use titanium bats in ASA or USSSA league play. ny conclusions regarding the safety of the game which are drawn from results obtained for titanium bat are irrelevant since these bats have been banned from play for the last 12 years.
In addition, since 2002, both the Easton Synergy and Miken Ultra II composite bats have both been banned for use by the ASA and USSSA. Both bats fail to pass the USSSA BPF test when the ball impact location is scanned along the barrel instead of testing only at the COP. Both bats also fail to pass the ASA 2004 test as per ASTM F2219 which uses the higher ball impact speed and accounts for the bat's inertia and impact location. Again, any conclusions drawn from the data for these bats is irrelevant since players cannot legally use them in ASA and USSSA sanctioned games.
The two remaining bats in this study, the DeMarini Doublewall Classic and the DeMarini Ultimate Weapon single wall bat both pass the 43.8 m/s (157.7 km/h) limits imposed by the current ASA F2219 test and are both considered legal bats, though the double-wall bat does outperform the single-wall bat. The warnings presented by McDowell and Ciocco regarding the performance of titanium and high performance composite bats are rendered somewhat irrelevant since these bats are not allowed to be used in play.
The alarming conclusions McDowell and Ciocco make regarding the dangers inherent to the game of softball are not representative of the current state of the game. The bats which this study declares to be dangerous are not representative of bats currently used by slow-pitch softball players playing by ASA or USSSA rules. And, the performance standards used in this study to classify bats as being dangerous had either been modified or abandoned before this paper was accepted, and do not represent the current state of the game.
Respectfully,
Daniel A. Russell, Ph.D.
Associate Professor of Applied Physics
Kettering University, Flint, MI, USA
References
1. M McDowell and M V Ciocco, A controlled study on batted ball speed and available pitcher reaction time in slowpitch softball. Br J Sports Med 2005; 39: 223-225.
2. L.V. Smith and J.T. Axtel, "Mechanical Testing of Baseball Bats," J. Testing Eval., 31(3), 210-214 (2003).
4. A.M. Nathan, "Characterizing the performance of baseball bats," Am. J. Phys., 71(2), 134-143 (2003).
5. L. Smith, J. Broker and A. Nathan, "A Study of Softball Player Swing Speed," in: Sports Dynamics Discovery and Application, Edited by A. Subic and F. Alam (RMIT University, Melbourne Australia, 2003), 12-17.
6. G. Fleisig, N. Zheng, D. Stodden and J. Andrews, "Relationship between bat mass properties and bat velocity," Sports Engineering, 5(1), 1-8, (2002).
7. K. Koenig, N. Mitchel, T. Hannigan, and J. Clutter, "The influence of moment of inertia on baseball/softball bat swing speed," Sports Engineering, 7(2), 105-118 (2004).
The article published by Dr. Hsu and colleagues [1] appears to
furnish a new mechanism for neurological decompression illness, related to
intrapulmonary right-to-left shunting. However, the authors’ explanation
of the mechanism of injury in their patient is not supported by a more
detailed analysis.
During a scuba dive, the tissue partial pressure of inert gas
(nitrogen if the diver is brea...
The article published by Dr. Hsu and colleagues [1] appears to
furnish a new mechanism for neurological decompression illness, related to
intrapulmonary right-to-left shunting. However, the authors’ explanation
of the mechanism of injury in their patient is not supported by a more
detailed analysis.
During a scuba dive, the tissue partial pressure of inert gas
(nitrogen if the diver is breathing air) increases. During decompression,
if the tissue gas tension exceeds atmospheric pressure, gas
supersaturation can occur, causing in situ bubble formation. After scuba
diving, venous gas bubbles are frequently detectable using ultrasound, but
rarely cause symptoms because they are removed by the pulmonary capillary
network. As pointed out in Dr. Hsu’s article, several authors have
observed a statistical relationship between neurological decompression
illness and the presence of inter-atrial shunts (e.g. a patent foramen
ovale, PFO). A PFO is presumed to allow entry of venous bubbles into the
arterial circulation, where they can cause systemic vascular occlusion or
injury. In order for this process to occur, two factors must be present:
(a) a right-to-left shunt and (b) venous gas embolism. If this mechanism
is correct, the same phenomenon should occur with intrapulmonary shunts,
such as in Osler-Weber-Rendu disease. Indeed, the sudden loss of
consciousness during ascent from the dive in a patient with Osler-Weber-
Rendu disease appears to support such a mechanism.
However, the dive depth was only to a depth of 5 feet (1.15
atmospheres absolute). Thus, the tissue PN2, even after an infinitely long
dive, could have been only 690 mmHg, hence rendering supersaturation
impossible. The threshold depth for in situ bubble formation is believed
to be around 12 feet [2]. Assuming gas bubbles to have been the cause of
unconsciousness in Dr. Hsu’s patient, a more plausible explanation is
pulmonary barotrauma caused by breath-holding or regional pulmonary gas
trapping.
References:
1. Hsu Y-L, Wang H-C, Yang P-C. Desbaric air embolism during
diving: an unusual complication of Osler-Weber-Rendu disease. Br J Sports
Med 2004;38:e6.
2. Eckenhoff RG, Olstad CS, Carrod G. Human dose-response
relationship for decompression and endogenous bubble formation. J Appl
Physiol 1990;69:914-8.
Although this study found that exercise improves some aspects of
cognitive performance, it also confirmed a recent meta-analysis[1] in
concluding that folic acid supplementation does not significantly
benefit cognition. A recent article by our group suggested that much of
the relationship between folate levels and cognition may be attributed to
exercise[2] because exercise is known to raise folate leve...
Although this study found that exercise improves some aspects of
cognitive performance, it also confirmed a recent meta-analysis[1] in
concluding that folic acid supplementation does not significantly
benefit cognition. A recent article by our group suggested that much of
the relationship between folate levels and cognition may be attributed to
exercise[2] because exercise is known to raise folate levels.[3]The current
article further reinforces the need for research investigating the
interaction of exercise, folate, and cognitive performance.
References
1. Balk EM, Raman G, Tatsioni A, Chung M, Lau J, Rosenberg IH. Vitamin
B6, B12, and folic acid supplementation and cognitive function: a
systematic review of randomized trials. Arch Intern Med 2007; 167(1): 21-
30.
2. Middleton LE, Kirkland SA, Maxwell CJ, Hogan DB, Rockwood K.
Exercise: a potential contributing factor to the relationship between
folate and dementia. J Am Geriatr Soc 2007; 55(7): 1095-8.
Dres. Gore and Hahn suggest that the significant mean increase of 6%
in total haemoglobin mass (tHbmass) which we observed after altitude
training in elite junior swimmers might to a major extend be attributed to
few erroneous measurements after altitude training. As already discussed
in the paper, we agree that an increase of about 24% is astonishingly
high. However, as pointed out, we were not the...
Dres. Gore and Hahn suggest that the significant mean increase of 6%
in total haemoglobin mass (tHbmass) which we observed after altitude
training in elite junior swimmers might to a major extend be attributed to
few erroneous measurements after altitude training. As already discussed
in the paper, we agree that an increase of about 24% is astonishingly
high. However, as pointed out, we were not the first to observe a wide
inter-individual variability in the erythropoietic response to altitude
exposure. Large inter-individual differences in the hypoxia-induced
increase in erythropoietin are well known [1-3] and a wide inter-
individual variation has also been described for the increase in red blood
cell volume after altitude training leading to the hypothesis that there
might be “responders” and “non-responders” to altitude training [1].
Furthermore, measurements with Evans Blue dye [1] and with technetium
labelling (cited in 4) yielded comparable significant increases in tHbmass
or total red blood cell volume, respectively, when differences in time and
altitude of exposure are taken into account. It was the aim of our study
to find out if changes in tHbmass after altitude training might be
predicted by the erythropoietin response after short exposure to moderate
normobaric hypoxia. We did not want to provide an answer to the question
whether or not 3 weeks of training at moderate altitude leads to an
increase in the tHbmass of elite junior swimmers. Therefore, we did not
include a control group of elite junior swimmers performing equivalent
training at sea level.
We thank Dres. Gore and Hahn for drawing our attention to the paper
of Parisotto et al. [5] reporting changes in tHbmass after administration
of r-HuEPO. This paper, unfortunately, escaped our attention because
title, abstract and key words did not refer to tHbmass. Two major
differences between this paper and our study might account for the
considerably larger variability in tHbmass in our subjects: First,
Parisotto et al. injected doses of erythropoietin based on body weight
which results in a much smaller inter-individual variability in plasma
levels of erythropoietin than natural exposure to altitude.
Secondly, we
studied elite junior athletes, who might increase total haemoglobin more
than adult elite athletes and might also show greater variability when
subjected to endurance training at altitude as they still experience
growth and maturation. To our knowledge, the erythropoietic response of
adolescent athletes to altitude training has not been studied so far.
We are well aware of the fact that any leak in the CO-rebreathing
system would result in erroneously high values for blood volume.
Therefore, we performed our measurements with great care to avoid such
leakages. Should nevertheless any leakage have occurred in some
measurements, it can be expected to be distributed randomly between
baseline and post-exposure measurements. Therefore, the reported average
increase in tHbmass of 6% should not have been affected substantially,
while erroneous measurements could at least in part account for a lack of
correlation between the increase in plasma erythropoietin levels and
tHbmass. However, as mentioned in our paper, there are other
investigations that could not find a significant correlation between
tHbmass and erythropoietin response under comparable circumstances.
Furthermore, C.J Gore and A. G. Hahn refer to the study of Burge and
Skinner [6] and state that the small dose of CO used in our study and the
larger rebreathing volume are suboptimal. Burge and Skinner recommend an
increase in COHb of at least 6.5 % to achieve a good degree of sensitivity
and precision for the determination of tHbmass. However, they also admit
that in another study of Thomsen et al. [7] changes in COHb > 5%
reduced the coefficient of variation only marginally and that an increase
of COHb of about 5 % also produces acceptable results in the measurement
of tHbmass. The CO-volume of 0.85 ml • kg-1 in our study induced a mean
increase in COHb of 5.2% which thus cannot be considered as “suboptimal”.
In summary, we conclude that the mean 6 % increase in tHbmass, which
is in agreement with increases reported by other investigators [1,4],
cannot be explained by erroneous measurements.
References
1. Chapman RF, Stray-Gundersen J, Levine BD. Individual variation in
response to altitude training. J Appl Physiol 1998; 85: 1448-1456.
2. Richalet J-P, Souberbielle J-C, Antezana A-M, et al. Control of
erythropoiesis in humans during prolonged exposure to the altitude of 6542
m. Am J Physiol 1994; 266: R756-R764.
3. Ge RL, Witkowski S, Zhang Y, et al. Determinants of
erythropoietin release in response to short-term hypobaric hypoxia. J Appl
Physiol 2002; 92:2361-2367.
4. Rusko HK, Tikkanen HO, Peltonen JE: Altitude and endurance
training. J. Sports Science 2004; 22: 928-945.
5. Parisotto R, Gore CJ, Emslie KR, et al. A novel method utilising
markers of altered erythropoiesis for the detection of recombinant human
erythropoietin abuse in athletes. Haematologica 2000; 85: 564-572.
6. Burge CM, Skinner S. Determination of haemoglobin mass and blood
volume with CO: evaluation and application of a method. J Appl Physiol
1995; 79: 623-631.
7. Thomsen JK, Fogh-Andersen N, Bülow K, Devantier A. Blood and
plasma volumes determined by carbon monoxide gas, 99m Tc-labelled
erythrocytes, 125 I-albumin and the T 1824 technique. Scand J Clin Lab
Invest 1991; 51: 185-190.
I have suggested that what carries the qi in our body is the volatile
and smart NO (nitric oxide):
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1180462
Further elaboration on such a netting (as proposed by the chinese via
the meridians) may suggest a simpler way to test the tai-chi effect on the
metabolic syndrome. I would be glad to collaborate on such a study.
here is my recent NO...
I have suggested that what carries the qi in our body is the volatile
and smart NO (nitric oxide):
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1180462
Further elaboration on such a netting (as proposed by the chinese via
the meridians) may suggest a simpler way to test the tai-chi effect on the
metabolic syndrome. I would be glad to collaborate on such a study.
here is my recent NO article:
http://www.notes.co.il/dina/32099.asp
We would like to thank Russell for his letter because we feel the
subject of safety in the sport of men’s slow-pitch softball has been
ignored for too long and it is refreshing to see that others are also
taking notice. An increase in the awareness of this subject through
discussions and scientific publications will help lead to required, well-defined, safety standards in the sport of softball. Unfort...
We would like to thank Russell for his letter because we feel the
subject of safety in the sport of men’s slow-pitch softball has been
ignored for too long and it is refreshing to see that others are also
taking notice. An increase in the awareness of this subject through
discussions and scientific publications will help lead to required, well-defined, safety standards in the sport of softball. Unfortunately, we take
issue with some of Russell’s comments.
The comments by Russell about publishing this paper in an American
journal are without merit. The BJSM is an excellent Journal that is truly
concerned with sports safety. Suggesting or implying that BJSM’s review
process or standards are sub par compared to American Journals is
completely unwarranted.
Russell’s comments on outdated performance standards are misleading.
At the time this paper was prepared the performance standards mentioned in
the paper were in use. The ASTM F2219 standard that he mentioned was
adopted by the ASA association on January 1st, 2004. In addition, it
takes time for a peer review article to be published. We are well aware of
the recent changes in laboratory performance-based testing. In terms of
the sports of softball and baseball, the ASTM is a laboratory performance-
based organization, not a safety-based organization. We are primarily
concerned with safety studies, not laboratory performance standards since
actual field-test studies are the only true test of player safety. We feel
using human reaction time studies and research will lead to a truly safe
sport for the recreational softball player.
The following is attached to each scope section 1.4 with every ASTM
performance standard in the sports of softball and baseball; “This
standard does not purport to address all the safety concerns, if any,
associated with its use. It is the responsibility of the user of this
standard to establish appropriate safety and health practices and to
determine the applicability of regulatory limitations prior to use”.
Based on this fact, Russell’s comments on the use of ASTM standards
are not sufficient to rely on as a safety standard for the sport of
softball or baseball. Again, our primary focus is on the safety aspect of
the sport of slow-pitch softball, not comparisons and evaluations of the
various ASTM laboratory performance standards used by the different
softball associations. There are some important points not mentioned by
Russell that need to be addressed concerning the new ASTM performance
standard, ASTM F2219. Only one of the at least six (6) slow-pitch
associations in the United States are currently using ASTM standard F2219.
In addition, it still remains a laboratory performance-based test which
has its shortcomings compared to real-world field-tests. One very obvious
loophole in the ASTM F2219 test is already being exploited by bat
manufacturers to produce bats that pass the “98 mph (43.8 m/s) limit” but
perform above this limit in real-world conditions.
It should also be mentioned that the ASA, despite claiming to adopt
the ASTM F2219 with a 98 mph (43.8 m/s) limit, still allows bats that
surpass the limit to be used. These “grandfathered” bats include the Miken
Freak, Mizuno Crush, Easton Synergy 2, etc. We realize the associations
may be under a lot of pressure not to ban bats, but it appears that safety
is being compromised in this case. Attend any ASA sponsored tournament and
you will see that most teams are using these “grandfathered” bats because
they out perform other ASA bats. The end result is that the ASTM F2219
with a 98 mph (43.8 m/s) limit is not even being incorporated into the
game today.
There have been a few important safety studies in the sport of
baseball that Russell failed to mention. A safety study by Owings, et
al.,[1] investigated pitcher reaction time as a consideration in design
constraints for baseballs and baseball bats for various age groups. They
found that for the 16-year age group, a minimum reaction time of 0.409
sec. was necessary to reduce the potential for serious or catastrophic
injury. Accounting for ball deceleration, the maximum initial batted-ball
speed to allow 0.409 sec. is 39.1 m/s. While, as Russell points out “The
ASA has set a maximum Batted-Ball Speed limit of 43.8 m/s (157.7 km/h)
using the high-speed impact test F2219”, this equates to an available
pitcher reaction time of only 0.365 sec, which is clearly a significant
safety concern. We are basing our conclusions on published, peer reviewed
literature that at least 0.409 sec. is needed for a player to determine,
decide, and react to a batted-ball[1].
Another study initiated by the NCAA tested a variety of bats on a
specially designed batting machine located at the University of
Massachusetts in Lowell[2]. The recommendation based on this research
effort was to drop the exit speed of a batted-ball to no more than 149.7
km/h (93 mph) in collegiate baseball. In this case this equates to an
available reaction time of 0.420 sec. Again, the 0.365 sec. the ASA
believes is “safe” is much less and illustrates the significant safety
concern.
A recent review article by Nicholls, et al.,[3] investigates the
current literature relating to impact injuries and the role of equipment
performance in the sport of baseball. They surmise that batted-ball
speeds from non-wood bats can reach velocities potentially lethal to
defensive players. Another study by Nicholls, et al.,[4] compared ball
exit velocity between metal and wooden baseball bats. The results of this
study indicate that a “certified” metal bat swung by an experienced hitter
can produce ball exit velocities exceeding that demonstrated by a robotic
hitting machine, which is what is currently used in the sport to determine
bat safety. This illustrates the necessity for field-testing research.
The published literature on pitcher reaction time consistently
supports our claim that the sport is much too dangerous for the
recreational player and we stand by our research findings. Obviously the
only fatal (literally) flaw here is to trust the various softball
associations to set safety standards. An independent organization needs to
set one comprehensive safety standard for the entire sport of Slow-Pitch
Softball.
Russell’s comments on illegal and banned bats are again, misleading.
We used titanium bats as a reference due to the fact that they were
outlawed immediately by their excessive batted-ball speeds. Today’s
composite bats produce batted-balls speeds in excess of titanium bats but
have been in use for the past five years. Our field-test studies indicate
that today’s high-tech composite bats consistently outperform titanium and
aluminium bats yet there are still allowed to be used. The real question
is: Why are bats that consistently outperform the banned Titanium bats
legal for play in some associations today?
As for the comment that this study would have been relevant 5 years
ago, the fact is this study would have been impossible 5 years ago because
neither the Synergy nor the Ultra II were introduced until 2003.
Furthermore, at the time of this study, these bats were legal and still
are legal in some associations. For example the Synergy is still legal in
USSSA and SSUSA play and the Ultra II is still legal in SSUSA play.
Obviously, as with most research, there are still many questions to
be answered and we are continuing our field-testing research studies of
slow-pitch softball equipment in order to improve the safety of the game.
Along these lines we have another field-testing research study, soon to be
published, that also indicates that there is a significant safety risk to
slow-pitch softball pitchers. From Owings published results[1], at least
0.409 sec. was deemed necessary to reduce the potential for serious or
catastrophic injury. Below is a subset of the data in this upcoming paper.
The initial batted-ball speeds (BBSi) and the available pitcher reaction
times (APRT) are listed for all softball associations
ASA/USSSA/NSA/ISA/SSUSA and ISF legal non-composite and composite bats.
Non-Composite ASA 2005 Model Bat: BSSi = 45.5 m/s, APRT = 0.351 sec.
Non-Composite USSSA/NSA/ISA/SSUSA/ISF 2005 Model Bat: BBSi = 45.5
m/s, APRT = 0.351 sec.
Composite ASA 2005 Model Bat: BBSi = 45.0 m/s, APRT = 0.355 sec.
Composite USSSA/ISA/NSA/SSUSA 2005 Model Bat: BBSi = 47.4 m/s, APRT =
0.338 sec.
Wooden bat (Reference): BBSi = 38.0 m/s, APRT = 0.421 sec.
The results indicate that there still exists a serious safety issue
that has not been addressed by the softball associations. To that end, we
are continuing our field-testing research efforts and hope that one day
soon a uniform safety standard will be applied to the sport, which we feel
will ultimately reduce serious and catastrophic injures as well as
fatalities that have occurred in the sport over the past few years. The
authors are only concerned with the safety of the game of softball and
having one uniform safety standard for the entire sport of slow-pitch
softball.
In closing, we challenge Russell to present published batted-ball
speed testing results from a truly independent source. He failed to
disclose that he has a conflict of interest when it comes to the
laboratory testing of softball bats by being affiliated directly or
indirectly with at least one softball association, hence his repeated
references to a new ASTM standard that has been adopted by only one
softball association. The authors of this study have no, nor are seeking
an affiliation with any bat or ball manufacturer or softball association
and conduct truly independent field-testing research on softball and
baseball bats and balls free from outside influence. The same cannot be
said of Russell and his colleagues who appear to be actively engaged in
discussions with bat manufactures concerning laboratory testing of
softball bats.
References
1. Owings, T. M., Lancianese, S. L., Lampe, E. M., and Grabiner, M.
D. (2003) Influence of Ball Velocity, Attention, and Age on Response Time
for a Simulated Catch. Medicine & Science in Sports and Exercise. Vol.
35, No. 8, pp. 1397-1405.
3. Nicholls, R.L., Miller, K., Elliott, B.C. (2004) Review: Impact
injuries in baseball: prevalence, aetiology and the role of equipment
performance. Sports Medicine 34(1): 17-25.
4. Nicholls, R.L., Elliott, B.C., Miller, K., Koh, M. (2003) Bat
kinematics in baseball: implications for ball exit velocity and player
safety. Journal of Applied Biomechanics 19: 283-294.
5. McDowell, M, Ciocco, M. and Morreale, B. (2005). "A Composite
Softball Bat Revolution: Why the Pitcher has Little Time to React to a
Batted-Ball". The Sport Journal Vol. 8(1).
6. McDowell, M. (2004). "Assessment of Softball Bat Safety
Performance Using Mid-Compression Polyurethane Softballs". Sports
Biomechanics Vol. 3(2) 185-194.
In the last years, validity and reliability of tests used is exercise
science has gained a lot of attention. Since the review of Atkinson and
Nevill (1998), many works has published addressing these matters.
Baltaci et al., in the present work, assessed the validity of three
different forms of sit-and-reach (SR) test and compared the results with
flexibility of hip joint for flexion using a go...
In the last years, validity and reliability of tests used is exercise
science has gained a lot of attention. Since the review of Atkinson and
Nevill (1998), many works has published addressing these matters.
Baltaci et al., in the present work, assessed the validity of three
different forms of sit-and-reach (SR) test and compared the results with
flexibility of hip joint for flexion using a goniometer. However, authors
used the Pearson Correlation Coefficient (r) as a validity scale.
Since the work of Altman and Bland (1983), it is well know that r is
not a good way to assess validity or reliability. Really, this notion was
already shown before (Hallman and Teramo, 1981). The reasons, well
described in the work of Altman and Bland (1983), can be resumed in two
points. First, Pearson r is the relation between variation of values
across individuals and variation within individuals. If variations between
individuals are large, correlation will be large, independently of
variation within individuals. In this case, variation between individuals
is large, what can be demonstrated by large standard deviations in Table 1
of the article.
Second, if we want to use this approach to validity, we need to
regress values of one method (in the case of different scales) and
estimate de validity by the Standard Error of Estimate (SEE). The problem
here is that SEE is a value that will change depending of the distance
from the mean.
Authors also stated that SR and BSSR are highly related to hamstrings
flexibility and the CSR test was not related. But, at conclusion, authors
stated that all SR tests had similar criterion related validity. Based on
the r coefficients, all three tests are significantly related and none had
a strong relation. CSR presented a week correlation (0.22 and 0.21,
comparing with GML, as the authors) and SR and BSSR had a moderate
correlation (SR=0.63, BSSRL=0.37, BSSRR=0.50).
Even if Pearson r could be accepted as a good estimate of validity,
the conclusions of the authors appears to be some confusing.
I read with interest the study by Panics et al on the effect of
proprioceptive training on joint position sense (JPS)at the knee. The
authors report a significant improvement in JPS in terms of reduction in
mean absolute error after the training. I have several concerns, however,
regarding the methods used by the author to assess JPS. First, looking at
Fig 1, one can ask as to how the positioning of t...
I read with interest the study by Panics et al on the effect of
proprioceptive training on joint position sense (JPS)at the knee. The
authors report a significant improvement in JPS in terms of reduction in
mean absolute error after the training. I have several concerns, however,
regarding the methods used by the author to assess JPS. First, looking at
Fig 1, one can ask as to how the positioning of the electrogoniometer was
properly controlled between sessions and between participants. Reports
have shown that even slight change in reference points with regard to
anatomical landmarks can lead to substantial error in measurements (see
Szulc,et al (2001) Med Sci Monit, 7(2), 312-315). Second, given that the
leg was moved passively by one experimenter, how tactile feedback arising
from contact with the skin was controlled? And what about the speed of
mobilization? One can easily see the difficulty for accelerating the leg
at the reported constant speed (ie., 10 deg/s) at 10 vs 80 deg in the
range tested. Such factors, when not properly controlled, can lead to
spurious cues influencing participants' ability to report joint angle. It
is also not clear to me as to why the intervention group initially
displayed poor JPS as compared to control. In the same vein, the range of
errors for JPS reported by the authors (8.21 -9.78 deg) is quite at odds
with the range reported in previous studies for normal young adults
(typically <5 deg, see Barrett et al (1991). J Bone Joint Surg Br, 73-
B(1), 53-56.).
I think the issue of measuring the impact of proprioceptive training on
proprioception is important for rehabilitation of sport injuries, but we
also need to be careful as to how we measure this complex sensation.
I am writing again, not to engage in a war of words with the authors, but to offer some suggestions which might strengthen the safety concerns reached in the paper by McDowell and Ciocco.[1] Unfortunately, it appears that the authors misunderstood the point of my first letter and assumed that I was criticizing their conclusions regarding the safety in slow-pitch softball. I do not disagree with their conclusion...
I am writing again, not to engage in a war of words with the authors, but to offer some suggestions which might strengthen the safety concerns reached in the paper by McDowell and Ciocco.[1] Unfortunately, it appears that the authors misunderstood the point of my first letter and assumed that I was criticizing their conclusions regarding the safety in slow-pitch softball. I do not disagree with their conclusion that high performance bats present a significant safety risk. My letter attempted to raise three points: (i) that the ASTM 1890 standard which the authors used to define a safe reference APRT from a recommended safe initial BBS" does not accurately predict field performance and therefore should probably not be used to establish a baseline for safety arguments; (ii) that one of the "two major national softball associations in the United States" the authors refer to in their paper has long since abandoned this standard in favor of one which much more accurately predicts field performance of bat, though it does have its own unique problems; and (iii) that I felt the choice of bats used in this study do not represent bats currently used by the majority of those who play recreational softball at the time this paper was finally published.
I will refrain from attempting to refute the authors' professionally offensive claim to be the only researchers capable of "truly independent research" in the area of softball and related performance and safety issues, and I will not respond to their completely unprofessional attacks on my own integrity and research ethics. I would, however, appreciate the opportunity to respond to their challenge to "present published batted-ball speed testing results from a truly independent source." I have to admit I'm not entirely sure I understand what McDowell and Ciocco consider to qualify as a "truly independent source." I am, however, aware of a very thoroughly conducted field study comparing wood and metal baseball bats which resulted in several publications.[2-4] This field study, which used 19 players from high school, college and minor leagues, had hitters swinging at pitched balls with six different metal bats and one wood bat. Multiple high-speed video cameras were used to measure the trajectories of the ball and bat before and after the collision. The study found that metal bats can significantly outperform wood bats and the various published papers provide a wealth of information that could be used to derive APRT values and other data regarding the safety of the game. This study does not directly satisfy the challenge because it deals with baseball bats, not slow-pitch softball bats. However, it is an excellent example of how a proper field study should be carried out, both in terms of the experimental methods which guarantee reliability of the data and statistical repeatability of the results. Such an extensive field study is very expensive to conduct and requires external funding to be brought to fruition. Unfortunately I would guess that such external funding, in this case from the SGMA and NCAA, is what might disqualify this field study from being considered "truly independent research." I am also aware of two field studies concerning men's slow pitch softball, one conducted in Montgomery in 2001 and the other in Charlotte in 2002, which have not yet been published because the researchers are still in the process of analyzing several hundreds of gigabytes of high speed video footage from multiple cameras which were used to record the motion of the bat and ball in 3-D. These two studies were also conducted with a high degree of attention to detail and thoroughness in experimental procedure. I hope these studies will be published in the very near future, as they will provide much needed information on the performance and safety of bats in slow-pitch softball. However, these studies will also probably not count as "truly independent research" since they were funded, at least in part, by the ASA.
I am also aware of a relevant paper by Robert Adair [5] which addresses issues regarding the safety of slow-pitch softball and pitcher reaction times remarkably similar to those raised by McDowell and Ciocco. Adair's paper was published in 1997, long before high performance composite bats, and yet he was able to predict the dangerous impact such bats might have on the game. Adair doesn't use the term "available pitcher reaction time" but he does show similar data for reaction times and comes to the same conclusion that elastic polyurethane softballs hit with high performance softball bats do not allow the pitcher enough time to react to a line drive, and thus present a safety hazard to the game of softball. Adair's paper also raises two additional points regarding safety which are easily verified through a simple computer calculation. I would like to share these points with McDowell and Ciocco because it would make the arguments for safety in their paper much stronger. The calculation plots the trajectory of a softball leaving the bat at a height of 0.8 m above home plate, and with an initial angle of 6.0 degrees above the horizontal so that it follows a line drive path towards the pitcher who is standing 15.24 m away. The effects of air resistance are included during the entire path of the ball using the approach by Giordano [6] which accounts for the fact that air resistance depends on the square of the ball speed, and thus continuously changes during the ball's flight. This results in slightly different APRT values from those reported by McDowell and Ciocco since they used a single constant air drag reduction to obtain an average ball speed for all cases. For the discussion below I use an initial batted ball speed for a composite bat of 167.6 km/h which was extracted from Table 2 of the McDowell and Ciocco paper by removing the constant air drag factor. I compared this calculation with that for a "recommended safe initial BBS of 137.2 km/h." The results of this simple calculation are as follows:
The ball hit by the "safe" bat with BBSi = 137.2 km/h = 38.1 m/s = 85.3 mph arrives at the pitcher in a time of APRT = 0.420s, while the ball hit by the composite bat with BBSi = 167.6 km/h = 46.55 m/s = 104.1 mph arrives at the pitcher in a much shorter time of APRT = 0.350s. My calculated APRT is shorter than that of McDowell and Ciocco due to our different treatments of air resistance. It would appear that correctly accounting for air resistance makes the safety issue even more pronounced. In any case, as expected, the pitcher will have significantly less time to react to the ball hit by the composite bat.
More importantly, perhaps, are the speeds of the balls when they reach the pitcher. The ball hit by the safe bat will be travelling at 35.3 m/s (78.9 mph) when it hits the pitcher, whereas the ball hit by the composite bat will still be travelling with a speed of 43.2 m/s (96.6 mph) when it hits the pitcher. Both hit balls have lost a significant fraction of their initial velocity due to air friction, but the ball from the composite bat is still travelling at a very dangerous speed when it reaches the pitcher. This faster speed means more momentum and more kinetic energy goes into the collision with the pitcher's body. Furthermore, since the COR of the ball decreases as ball speed increases, the higher ball speed also means that the ball will behave less elastically when it hits the pitcher. It should be no surprise that when players are hit by balls from high performance metal and composite bats, the injuries are more severe then they might have been from a ball hit by a "safe" bat.
Thirdly, this simple calculation shows that when the ball from the safe bat arrives at the pitcher's mound it will be 1.55 m (5.08 ft) above the ground. However, the ball hit by the composite bat will be 1.83 m (5.99 ft) above the ground when it reaches the pitcher. This is very important because it means that while the ball from the safe bat might hit the pitcher in the chest or shoulder, the ball from the composite bat (which is already arriving with a much faster speed in a shorter time) will strike the pitcher in the neck or face. A pitcher might be able to get his glove up to chest level in time, but would probably not be able to move it the additional 11 inches up to face level fast enough to intercept the ball hit by the composite bat.
The combination of these three factors: the shorter reaction time, the higher ball speed at impact , and the location of impact on the body provide a much stronger argument regarding safety than does the APRT alone.
In the final paragraph of their paper, McDowell and Ciocco state that the "use of lower compression balls may greatly reduce BBSs and allow the pitcher enough time to react to most batted balls." While I would agree with this statement, the data presented in Table 1 of their paper does not appear to support this conclusion as strongly as they state. If one looks at the data in Table 1, one finds that lowering the compression of the ball from 2371 N/.64cm (529 lb/in) to 1668 N/.64cm (372 lb/in) while keeping the COR constant at 0.47 only reduces the batted ball speed by 1.77 km/h (1.1 mph). This is not a significant reduction in BBS, and the corresponding APRT only increases by 0.005s, which does not seem significant enough to improve the safety of the pitcher. This reduction in BBS is also much less than the reduction in BBS of 4.67 km/h (2.9mph) which was measured during a field study of slow-pitch softball conducted in 2002, and to be published soon. In addition, according to the data in Table 1, one fines that a reduction in the COR from 0.47 to 0.40 while keeping the compression relatively constant (2371 vs. 2460) actually causes the batted ball speed to increase by 1.29 km/h (0.8mph). This completely contradicts what one would expect from a simple physics analysis of the ball-bat collision. Furthermore, is contradicts data from another slow-pitch field study, unfortunately also not yet published, which showed that lowering the COR by the same amount with the same constant compression actually lowered the BBS by 7.89 km/h (4.9 mph). Any one who has played softball with balls of varying compression and COR knows from direct experience that changing the ball properties has a significant effect on the resulting batted ball speed. The data in this paper not only fails to agree with other, unfortunately yet unpublished, field studies, but it also contradicts what players (as well as manufacturers and associations) know actually happens in the field. While McDowell and Ciocco are right in their recommendation that lowering ball compression and COR might make the game safer, the data as presented in this paper does not back up their recommendation, suggesting that perhaps a more accurate method of measuring batted ball speed should be implemented in future studies.
I have one final comment with regards to the authors' comments on the validity of field studies compared to laboratory tests. A serious potential problem with field studies is that the results depend very much on the caliber and ability of the players who participate in the study. This potential variation in skill between players is absent from a carefully controlled laboratory experiment. This issue is especially important if one is trying to draw conclusions concerning the safety of certain bats and one wishes to separate the performance qualities of the bat from the performance skill of the players who swing the bat. Here's an example of what I mean. I play recreational softball in a summer church league. We have a big, tall player on our team who played baseball in college 25 years ago. He uses a 32oz, single-walled aluminum bat (he says the newer high-tech composite bats feel too light), and yet, almost every time he steps up to the plate he routinely punches the ball over the center field wall, more than 300 feet away. If this individual had participated in the McDowell and Ciocco study his mean BBS values for the aluminum single-wall bat would far exceed the 134.0 km/h reported in Table 2, and would probably approach values for Titanium and composite bats. Furthermore, the APRT for a line drive from this player using his single-walled bat would be much shorter than the 0.409s reported for a single-walled bat in Table 3. I'm reminded of the 1980's slowpitch giant Carl Rose, who routinely hit softballs over 400 ft using a singlewall aluminum bat, and embarked on a quest to hit a softball out of every major league baseball field using a single-walled aluminum bat. A limitation of field studies is that they rely too much on the ability of the players who participate in the test, and require a relatively large number of players to ensure statistical reliability of the data. I would agree that as long as one is using "average" players and very carefully define what it means to be a player of "average" ability, then the point McDowell and Ciocco are making is valid. That is, high performance composite bats in the hands of an "average" player present a safety hazard to the game. However, a low performance single-wall aluminum bat in the hands of a high performance player also presents a safety hazard to the game, which the field study described in this paper does not account for.
The reason for a standardized laboratory test, such as ASTM F1890 or ASTM 2219 is to provide a way to measure the performance of bats in an accurate and repeatable manner without the variation introduced by the human element. Granted it is absolutely necessary to attempt to correlate the laboratory results with field studies to make sure the laboratory results fall within the range of performances measured by players in the field. As I attempted to explain in my first letter, F1890 completely fails in this regard. In contrast, while F2219 was being developed the laboratory results were correlated with field trials for the highest performing A and B-level players at two different national ASA tournaments. As such, the performance data obtained in the laboratory with F2219 attempts to predict the performance of a bat in the hands of some of the best human players currently playing the game. While F2219 does a much better job of predicting field performance, it is by no means a perfect standard and has its own unique set of flaws. Hopefully through persistent research some of these problems may be eventually resolved. I believe that any laboratory test which more closely predicts actual field performance of bats must be welcomed as a useful tool to ensure the safety and integrity of the game. Of course, if manufacturers chose to take advantage of loopholes (as they are currently doing) and if associations refuse to adopt the more accurate standard (like 5 of the six US softball associations have) and if those associations that do adopt the better test method don't use it correctly (by setting too high a limit or by grandfathering in dangerous bats) then the usefulness of the test method has been greatly diminished and the safety of the game is still in jeopardy.
Safety in the sport of softball is a very important issue. Is it vital that research which addresses this issue of safety be carried out in a professional manner with considerable attention to detail in the experimental process and diligent analysis of the data so that the reported results and conclusions are as accurate and relevant as possible.
These comments are respectfully submitted by
Daniel A. Russell, Ph.D.
Associate Professor of Applied Physics
Kettering University, Flint, MI
References
[1] M. McDowell and M. V. Ciocco, "A controlled study on batted ball speed and available pitcher reaction time in slowpitch softball," Br. J. Sports Med., 39, 223-225 (2005).
[2] J. Crisco, R. Greenwald, L. Penna, and K. Saul, "On measuring the performance of wood baseball bats," Engineering of Sport - Research Development and Innovation, Edited by A. Subic and S. Haake, p.193-200 (Blackwell Science, Oxford, 2000).
[3] R. M. Greenwald, L. H. Penna, and J. J. Crisco, "Differences in Batted Ball Speed with Wood and Aluminum Baseball Bats: A Batting Cage Study," J. Appl. Biomech., 17, 241-252 (2001)
[4] J.J. Crisco, R.M. Greenwald, J.D. Blume, & L.H. Penna, "Batting performance of wood and metal baseball bats," Med. Sci. Sports Exerc., 34(10), 1675-1684 (2002)
[5] R.K. Adair, "The Physics of Baseball: The Standardization of Balls and Bats for Recreational Softball," International Symposium on Safety in Baseball and Softball, ASTM STP 1313, Earl. F. Hoerner and Francis A. Cosgrove, Eds., p. 21-28 (American Society for Testing and Materials, 1997).
[6] N. J. Giordano, Computational Physics, (Prentice Hall, 1997), p.23-32.
Dear Editor:
I now better appreciate Prof. Noakes' reasons for using the words he used following his response to my eletter posted on the BJSM Blog, and consider the issue of "data exclusion" settled. However, I would like to make the following points to clarify my position and respond to Noakes' interpretation of the physiology:
1. I do not consider myself "wedded to the Hill model" because the "Hi...
Dear Editor,
In their paper [1], McDowell and Ciocco conclude that "BBS values in slowpitch softball exceed recommended safety limits imposed on the sport" and their "findings indicate that softball is perhaps more dangerous then most coaches, players and parents think." Had this paper been published in an American journal it might have attracted considerable attention from the news media due to its alarming conclusion...
Dear Editor,
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Dear Editor
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Dear Editor
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Dear Editor,
We would like to thank Russell for his letter because we feel the subject of safety in the sport of men’s slow-pitch softball has been ignored for too long and it is refreshing to see that others are also taking notice. An increase in the awareness of this subject through discussions and scientific publications will help lead to required, well-defined, safety standards in the sport of softball. Unfort...
Dear Editor,
In the last years, validity and reliability of tests used is exercise science has gained a lot of attention. Since the review of Atkinson and Nevill (1998), many works has published addressing these matters.
Baltaci et al., in the present work, assessed the validity of three different forms of sit-and-reach (SR) test and compared the results with flexibility of hip joint for flexion using a go...
Dear editor
I read with interest the study by Panics et al on the effect of proprioceptive training on joint position sense (JPS)at the knee. The authors report a significant improvement in JPS in terms of reduction in mean absolute error after the training. I have several concerns, however, regarding the methods used by the author to assess JPS. First, looking at Fig 1, one can ask as to how the positioning of t...
I am writing again, not to engage in a war of words with the authors, but to offer some suggestions which might strengthen the safety concerns reached in the paper by McDowell and Ciocco.[1] Unfortunately, it appears that the authors misunderstood the point of my first letter and assumed that I was criticizing their conclusions regarding the safety in slow-pitch softball. I do not disagree with their conclusion...
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