The following electronic only articles are published in conjunction with this issue of BJSM (see also pages 136 and 165)

Proprioceptive neuromuscular facilitation training induced alterations in muscle fibre type and cross sectional area

N Kofotolis, I S Vrabas, E Vamvakoudis, et al

Objectives: To compare the effects of proprioceptive neuromuscular facilitation (PNF) and isokinetic training on fibre type distribution and cross sectional area of the vastus lateralis muscle.

Methods: Twenty four male university students were divided into two equal groups: PNF training and isokinetic training (ISO). The training regimen for the PNF group consisted of three sets of 30 repetitions against maximal resistance, alternating two patterns of sequential movements of the right lower extremity: (a) toe flexion and ankle plantar flexion and eversion; (b) knee extension and hip extension, abduction, and internal rotation. The ISO group performed three sets of 30 repetitions alternating knee extension and flexion of the right leg at angular velocities of 180 and 90°/s in an isokinetic dynamometer (Cybex). Both groups trained three times a week for a total of eight weeks. Muscle biopsy specimens were obtained from the right vastus lateralis muscle before and after training.

Results: The mean percentage area of type IIB fibre was significantly decreased (p<0.01) after eight weeks of PNF training, whereas that of type IIA fibre was significantly (p<0.05) increased. The mean percentage area of ISO trained type IIAB fibres exhibited an augmentative pattern (p<0.01) with a parallel reduction (p<0.05) in type IIA. Percentage fibre type distribution exhibited a similar pattern.

Conclusions: Both PNF and ISO training alter fibre type distribution and mean cross sectional area. These changes occur in the type II fibre subgroup.

(Br J Sports Med 2005;39:e11) http://bjsm.bmjjournals.com/cgi/content/full/39/3/e11

Physical activity levels during phase iv cardiac rehabilitation in a group of male myocardial infarction patients

K Woolf-May, S Bird

Objective: To determine physical activity levels during phase IV cardiac rehabilitation in 31 male myocardial infarction patients (median age 62, range 53–77 years).

Methods: Patients recorded daily physical activity over 16 weeks in a diary. Diaries were analysed for total general physical activity (TGPA), leisure time physical activity (LTPA), and “active for life” exercise classes (AFL). Pre- and post-observation period (OP) subjects underwent a 10 m shuttle walking test (SWT) to determine changes in aerobic fitness. Rate of perceived exertion (RPE) determined exercise intensity. Estimated gross energy expenditure (EEE) was determined by a regression equation between RPE and Vo₂ (l min⁻¹ during SWT. A total of 97% of subjects were on lipid lowering medication.

Results: There were no correlations between Vo₂ (l min⁻¹) and body mass, therefore kcal min⁻¹ indicated activity intensity. There were no significant changes in physical activity patterns or in aerobic fitness. Estimated total LTPA (median 1376, range 128–3380 kcal week21) was less than that recommended to improve aerobic fitness and/or slow progression of coronary artery disease. Sixteen subjects attended a median of 29 (range 1–46) AFL during LTPA; one way ANOVA showed these subjects worked at greater EEE (AFL, n  =  16, 6.6 (standard deviation 1.4) v no-AFL, n  =  15, 5.1 (1.8) EEE kcal min⁻¹, p  =  0.017).

Conclusion: Physical activity was stable, but patients’ EEE appeared insufficient to improve aerobic fitness or slow progression of coronary artery disease. It was suggested that the promotion of LTPA and the availability of AFL classes should be reconsidered.

(Br J Sports Med 2005;39:e12) http://bjsm.bmjjournals.com/cgi/content/full/39/3/e12