Effects of 8-week strength training with two models of chest press machines on muscular activity pattern and strength.
The purposes of this study were to assess: (i) the effects of 8-week training programs with constrained-path and unconstrained-path chest press machines on 1-RM; (ii) the different activity patterns of selected arm and shoulder girdle muscles during push movement performed on the different machines; (iii) the transfer of the training effects from one machine to the other. Twenty healthy, sedentary women (mean+/-SD age, 24.8+/-1.0yrs), randomized to either the FM or CM strength training protocols were evaluated before and after the strength training program. Muscular activity signals were recorded by surface electromyography (sEMG) from eight muscles while each subject performed the exercise on each machine. Muscle strength was defined by a 1 repetition maximum (1-RM) test for each subject on each machine. Both machines were effective in improving 1-RM, but the 1-RM increased more in the FM than the CM. Adaptive change in the sEMG was observed in all muscles after training on the FM machine, but not within the stabilizers when training on the CM machine. The results suggest that training in an unconstrained condition provides a more effective method for improving inter-muscular coordination via adaptation of the motor strategy aimed at optimising muscular efforts.
Cacchio
Angelo
A
Department of Physical Medicine and Rehabilitation, School of Medicine, La Sapienza University of Roma, 00185 Roma, Italy. angelo.cacchio@tin.it
Don
Romildo
R
Ranavolo
Alberto
A
Guerra
Enrico
E
McCaw
Steven T
ST
Procaccianti
Rita
R
Camerota
Filippo
F
Frascarelli
Massimo
M
Santilli
Valter
V
D000328:Adult; D001132:Arm / Q000502:physiology*; D001696:Biomechanical Phenomena; D004576:Electromyography; D005260:Female; D006801:Humans; D018482:Muscle, Skeletal / Q000502:physiology*; D010806:Physical Education and Training / Q000379:methods*; D012782:Shoulder / Q000502:physiology*; D013909:Thorax; D014741:Video Recording