Changes in exercises are more effective than in loading schemes to improve muscle strength.
This study investigated the effects of varying strength exercises and loading scheme on muscle cross-sectional area (CSA) and maximum strength after 4 strength training loading schemes: constant intensity and constant exercise (CICE), constant intensity and varied exercise (CIVE), varied intensity and constant exercise (VICE), varied intensity and varied exercise (VIVE). Forty-nine individuals were allocated into 5 groups: CICE, CIVE, VICE, VIVE, and control group (C). Experimental groups underwent twice a week training for 12 weeks. Squat 1 repetition maximum was assessed at baseline and after the training period. Whole quadriceps muscle and its heads CSA were also obtained pretraining and posttraining. The whole quadriceps CSA increased significantly (p ≤ 0.05) in all of the experimental groups from pretest to posttest in both the right and left legs: CICE: 11.6 and 12.0%; CIVE: 11.6 and 12.2%; VICE: 9.5 e 9.3%; and VIVE: 9.9 and 11.6%, respectively. The CIVE and VIVE groups presented hypertrophy in all of the quadriceps muscle heads (p ≤ 0.05), whereas the CICE and VICE groups did not present hypertrophy in the vastus medialis and rectus femoris (RF), and in the RF muscles, respectively (p > 0.05). The CIVE group had greater strength increments than the other training groups (effect size confidence limit of the difference [ESCLdiff] CICE: 1.41-1.56; VICE: 2.13-2.28; VIVE: 0.59-0.75). Our findings suggest: (a) CIVE is more efficient to produce strength gains for physically active individuals; (b) as long as the training intensity reaches an alleged threshold, muscle hypertrophy is similar regardless of the training intensity and exercise variation.
1Department of Sport, Laboratory of Neuromuscular Adaptations to Strength Training, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil; 2Department of Health Science and Human Performance, University of Tampa, Tampa, Florida; and 3Department of Sport, Delboni Auriemo Diagnostic Imaging Sector: A Division of DASA, São Paulo, Brazil.
Rodrigo M
RM
Fonseca
Hamilton
H
Roschel
Valmor
V
Tricoli
Eduardo O
EO
de Souza
Jacob M
JM
Wilson
Gilberto C
GC
Laurentino
André Y
AY
Aihara
Alberto R
AR
de Souza Leão
Carlos
C
Ugrinowitsch
D000328:Adult; D015444:Exercise / Q000502:physiology; D006801:Humans; D008297:Male; D053580:Muscle Strength; D009929:Organ Size; D005082:Physical Exertion / Q000502:physiology*; D052097:Quadriceps Muscle / Q000033:anatomy & histology* / Q000502:physiology*; D055070:Resistance Training / Q000379:methods*; D055815:Young Adult