None listed
Conditions
Brief summary
Purpose: To verify if the execution of a low intensity single-joint exercise for knee extensors is an efficient stimulus to increase vastus lateralis motor units recruited during a subsequent multi-joint exercise. Methods: Nine healthy male subjects (23.33 +/- 3.46 years old) performed three bouts of exercise in which knee extension and leg press 45 degrees were executed in sequence. In low intensity sequence (R30) 15 unilateral knee extensions were followed by 15 repetitions of leg press 45 degrees with 30% and 60% of one maximum repetition load (1-RM), respectively. In the high intensity sequence (R60), the same order was used, but the load applied was 60% of 1-RM for both exercises. One single set of 15 repetitions of leg press 45 degrees at 60% of 1-RM was performed as control exercise (C). The surface electromyographic signal was recorded from the vastus lateralis muscle with a linear electrodes array. The root mean square (RMS) value was determined for each repetition of leg press 45 degrees and a linear regression was calculated with these results. The slopes of regression line were normalized by their initial values and then compared by one way Analysis of Variance (ANOVA) for repeated measures. Results: The slopes observed in C were significant lower than the slopes calculated in R30 and R60 (p < 0.05). Conclusion: The results suggest a higher recruitment of motor units when a single-joint exercise preceded the multi-joint exercise.
Interventions
Male subjects performed three bouts of exercise in which knee extension and leg press 45 degrees were executed in sequence. In low intensity sequence, 15 unilateral knee extensions were followed by 15 unilateral repetitions of leg press 45 degrees with 30% and 60% of one maximum repetition load (1-RM), respectively. In the high intensity sequence, the same order was used, but the load applied was 60% of one maximum repetition load (1-RM) for both exercises. One single set of 15 repetitions of le
Male subjects performed three bouts of exercise in which knee extension and leg press 45 degrees were executed in sequence. In low intensity sequence, 15 unilateral knee extensions were followed by 15 unilateral repetitions of leg press 45 degrees with 30% and 60% of one maximum repetition load (1-RM), respectively. In the high intensity sequence, the same order was used, but the load applied was 60% of one maximum repetition load (1-RM) for both exercises. One single set of 15 repetitions of leg press 45 degrees at 60% of one maximum repetition load (1-RM) was performed as control exercise. The bouts were performed in three different days with 48 to 96 hours between them. The surface electromyographic signal was recorded from the vastus lateralis muscle with a linear electrodes array during the multi-joint exercises.
Sponsors
Universidade de Brasilia
Study design
Allocation
Non-randomised trial
Intervention model
Single group
Primary purpose
Educational / counselling / training
Masking
Open (masking not used)
Eligibility
Sex/Gender
Male
Age
18 Years to 27 Years
Healthy volunteers
Yes
Inclusion criteria
Training experience of one year in resistance training practicing resistance exercises at least three times a week.
Exclusion criteria
Cronic or acute injuries in lower limbs or negative answers in Physical Activity Readiness Questionnaire - PAR-Q.
Outcome results
None listed