This randomized, parallel-group study evaluated the effects of an 8-week unilateral resistance training program with strength- and velocity-oriented loading on limb-specific load-velocity relationships and lower-limb asymmetry in male university team-sport players. Participants were randomly assigned to a strength-oriented training group, which trained at 80% of the limb-specific one-repetition maximum (1RM), or a velocity-oriented training group, which trained at 40% of the limb-specific 1RM. Both groups completed 16 supervised free-weight split-squat training sessions over 8 weeks. In each session, the non-dominant limb performed four sets of five repetitions, while the dominant limb performed three sets of five repetitions. All repetitions were performed with maximal intended concentric velocity and real-time velocity feedback. Limb-specific load-velocity relationships were assessed at baseline, Week 4, and Week 8. Lower-limb asymmetry, balance, unilateral jump performance, and basketball-specific change-of-direction performance were assessed at baseline and Week 8. The purpose was to determine whether the two training orientations produced different adaptations and whether the additional training volume assigned to the non-dominant limb influenced inter-limb asymmetry.
This study used a randomized, two-arm, parallel-group design. Following familiarization and baseline testing, eligible male university team-sport players were randomly allocated to either a strength-oriented training group or a velocity-oriented training group. Participants completed two supervised training sessions per week for 8 weeks, resulting in a total of 16 training sessions. The primary training exercise was the unilateral free-weight split squat. The strength-oriented group trained at 80% of the limb-specific one-repetition maximum, whereas the velocity-oriented group trained at 40% of the limb-specific one-repetition maximum. In both groups, the non-dominant limb performed four sets of five repetitions and the dominant limb performed three sets of five repetitions during each session. Repetitions were performed with maximal intended concentric velocity, with real-time velocity feedback provided to participants. Loads were adjusted when necessary to maintain the prescribed limb-specific training intensity. Assessments were conducted before the intervention and after completion of the 8-week intervention. An additional interim assessment was conducted at Week 4, after the first eight training sessions. Data from the Week 4 assessment were used for an exploratory interim analysis of limb-specific load-velocity relationships and between-limb differences in derived mean concentric velocity. The Week-8 assessment evaluated the effects of the complete intervention on unilateral strength, load-velocity characteristics, balance, unilateral jump performance, basketball-specific change-of-direction performance, and lower-limb asymmetry.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
23
Participants completed 16 supervised unilateral free-weight split-squat training sessions over 8 weeks, with two sessions per week and at least 48 hours between sessions. Each limb trained at 80% of its limb-specific one-repetition maximum. During each session, the non-dominant limb performed four sets of five repetitions, while the dominant limb performed three sets of five repetitions. Inter-set rest was 4 minutes. All repetitions were performed with maximal intended concentric velocity, with real-time velocity feedback. Training loads were prescribed using the individual limb-specific load-velocity relationship and adjusted when necessary to maintain the target training intensity.
Participants completed 16 supervised unilateral free-weight split-squat training sessions over 8 weeks, with two sessions per week and at least 48 hours between sessions. Each limb trained at 40% of its limb-specific one-repetition maximum. During each session, the non-dominant limb performed four sets of five repetitions, while the dominant limb performed three sets of five repetitions. Inter-set rest was 4 minutes. All repetitions were performed with maximal intended concentric velocity, with real-time velocity feedback. Training loads were prescribed using the individual limb-specific load-velocity relationship and adjusted when necessary to maintain the target training intensity.
School of Physical Education and Sports Science, South China Normal University
Guangzhou, Guangdong, China
Mean Change From Baseline in Single-Leg Countermovement Jump Height Inter-Limb Asymmetry at Week 8
Single-leg countermovement jump height was measured separately for the dominant and non-dominant limbs using a force-platform system. Inter-limb asymmetry was calculated as 2 × the absolute difference between the dominant- and non-dominant-limb values divided by the sum of the two limb values, multiplied by 100. The outcome is expressed as a percentage, with higher values indicating greater inter-limb asymmetry. The mean change from baseline to Week 8 was compared between the two training groups.
Time frame: Baseline and post-intervention at Week 8
Mean Change From Baseline in Y-Balance Test Composite Score Inter-Limb Difference at Week 8
Anterior, posteromedial, and posterolateral reach distances were measured separately for the dominant and non-dominant limbs using the Y-Balance Test. The composite score for each limb was calculated as the sum of the three reach distances divided by three times the limb length, multiplied by 100. The inter-limb difference was calculated as the absolute difference between the dominant- and non-dominant-limb composite scores and expressed in percentage points. Higher values indicate a larger inter-limb difference. The mean change from baseline to Week 8 was compared between the two training groups.
Time frame: Baseline and post-intervention at Week 8
Mean Change From Baseline in Limb-Specific Mean Concentric Velocity at Prespecified Relative Loads at Week
Individual limb-specific load-velocity relationships were established during the unilateral free-weight split-squat one-repetition maximum test using linear regression. Mean concentric velocity was derived separately for the dominant and non-dominant limbs at 30%, 45%, 60%, 75%, and 90% of the directly measured limb-specific one-repetition maximum. Velocity was expressed in meters per second. Higher values indicate faster concentric movement at the same relative load. Mean changes from baseline to the Week 4 interim assessment were evaluated by training group and limb.
Time frame: Baseline and interim assessment at Week 4
Mean Change From Baseline in Basketball Dribbling T-Test Directional Asymmetry at Week 8
Directional change-of-direction performance was assessed using left-side-dominant and right-side-dominant versions of the basketball dribbling T-test. Participants completed two maximal trials in each direction, and the fastest completion time for each direction was recorded in seconds. Directional asymmetry was calculated as the absolute difference between the left- and right-side completion times divided by the faster completion time, multiplied by 100. Higher percentage values indicate greater directional asymmetry. The mean change from baseline to Week 8 was compared between the two training groups.
Time frame: Baseline and post-intervention at Week 8
Mean Change From Baseline in Absolute Inter-Limb Difference in Unilateral Split-Squat One-Repetition Maximum at Week 8
Unilateral split-squat one-repetition maximum was measured separately for the dominant and non-dominant limbs using a progressive loading protocol. The absolute inter-limb difference was calculated as the absolute difference between the dominant- and non-dominant-limb one-repetition maximum values and expressed in kilograms. Higher values indicate greater inter-limb strength asymmetry. The mean change from baseline to Week 8 was compared between the two training groups.
Time frame: Baseline and post-intervention at Week 8
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.