Table 7

Expert opinion related to practical implementation of modifying impact loading variables, contact time and stiffness

Illustrative quotes
Cues to reduce impact loading variables
On the importance of considering loading and impact forces
Comparison of importance between loading (kinetics) and kinematics
Methods to measure and reduce impact loading variables in the clinic
“So I put a lot of emphasis on (reducing) the loading rate (to manage running injuries).” (1)
“I have a sense that many injuries are related to loading so we try to get everyone off their heels just because I know that reduces the rate of loading.” (4)
“I think loading rate anywhere is always a consideration and I think it's definitely related to injury wherever you're looking.” (5)
“I feel like injuries are the result of forces … We are trying to create a loading environment that promotes healing or prevents injuries.” (8)
“A lot of people believe that vertical loading rates are (important and) have been shown to be causally related, but I think the evidence is far too weak.” (13)
“Any intervention that decrease the vertical loading rate and will promote better impact behaviour, it means forefoot striking, higher cadence, landing closer to the centre of gravity, more knee bend, all those interventions will decrease anterior compartment syndrome and all the knee pathologies, the hip pathologies and the lower back … I don't believe that kinematics is really linked with pathology.” (10)
“As far as I'm aware, really, it's the kinetics that cause injury, not necessarily kinematics.” (11)
“And obviously there's issues around that (just looking at movement) because you're not measuring forces. So you're making a lot of assumptions.” (13)
“The rate of loading, I think, is directly correlated with the noise, with the sound when running.” (1)
“Some people use an increase in the cadence (to reduce impact) and I think that's a good broad global way to tell people who aren't gonna be followed closely.” (4)
“Running softly. I've heard that before. I've used that (to reduced impact loading variables). I don't, didn't find that was for me, one that has a lot of success with a lot people, they just struggle with exactly what to do when it comes to running softly.” (5)
“Probably the main measure of that (loading rate) clinically is—and the runner will say this—you can ‘hear’ the difference or ‘feel’ the difference.” (6)
“Talking to them about trying to land slightly softer as well as part of that. So they tend to, again, if you ask them to do that, it'll often shorten the stride, so the knee flexes a little bit, so they're not landing on a straight knee.” (12)
“Using those sort of cues around running softly, lightly, getting people to try and adjust their stride to decrease those impact forces.” (13)
Cues to reduce contact time
Consideration related to stiffness and an optimal range—implications to performance and injury“Increase in the lower limb stiffness improves performance, power production, rate of force development, and therefore will improve significantly their running performance.” (7)
“Stiffness can be—can help you to become more efficient, more economical.” (10)
“If we can create more plantar flexion stiffness then we can see a more efficient motor unit.” (11)
“Kick your heels towards your butt and we like that one just because it reduces the inertial parameters of the swing … what it does is it allows people to use their hamstrings, get them a little bit more stiffness (to improve performance).” (14)
“If I see the increased knee stiffness, I honestly encourage them to run softer so they can flex their knees a little bit more … Too much (stiffness) and you're really putting a lot on the tendons and the muscles. And too little of it is going through the skeletal systems.” (15)
“(Referring to stiffness) Some people might be Nerf balls, some people might be golf balls. And I think they are, and I think the evidence is really clear that they are very intrinsic tissue capabilities … Everybody doesn't have the same stiffness (in their) tendons.” (16)