Daniel J. Wilson

Efficacy of strength training in prepubescent to early postpubescent males and females: Effects of gender and maturity

There has been considerable debate concerning the benefits of children participating in weight training programs. With the potential benefits of such training in specific rehabilitation regimens, the safety/efficacy of weight training is a topic in need of scientific study. Fifty-two experimental and 39 control subjects participated in this study. A 2 x 2 x 2 (gender by treatment by Tanner stage) ANOVA was used to examine pre- to post-test differences in six strength measures, eight anthropometric measures, five motor performance measures, and one flexibility measure associated with participation in a 12-week progressive resistance programme. In addition, safety of the weight training programme was examined. For strength differences, there were two significant main effects favouring strength gains in males and four favouring the experimental group. For anthropometric changes, 3-way interactions occurred that were not easily explained. However, the predominant main effect was treatment; the experimental group generally experienced gains in body segment girths with decreases in skinfold thickness. For motor performance, the experimental group had greater improvements in three of five parameters. The experimental group also had significantly greater gains in flexibility. The weight training programme was associated with only one injury. These findings support the general observation that physical benefits can be gained safely by children who participate in a weight training programme.

Lumbar spinal moments in chronic back pain patients during supported lifting: A dynamic analysis

OBJECTIVES The main objective of this study was to test the hypothesis that peak L4/L5 moments (torque) placed on the lumbar spine by chronic back pain subjects are reduced using pain-reducing postural adaptations. A secondary objective was to determine the relation between lumbar moments while lifting and self-reported ratings of lower back pain. STUDY DESIGN Cohort using seven men with a history of chronic lower back pain. An inverse dynamic model was used to calculate L4/L5 forces and moments while performing five trials each of two lifting styles. Subjective ratings of lumbar back pain were taken before and after the lifts. RESULTS Significant (p < .001) differences were found between lifting postures on peak L4/L5 net reaction moments. Two distinct lifting profiles emerged characterized by the amount of lumbar spinal extensor musculature involved. Significant (p < .05) increases in pain were found after a bowed-back lifting style. CONCLUSIONS Peak L4/L5 net reaction moments were less (spine extensor loading) for a lifting posture that produced lower levels of self-reported lower back pain. The dynamic model proved reliable and useful for future study of the pathomechanics of lower back pain.