Cross education is modulated by set configuration in knee extension exercise

Area of Science:

• Exercise Physiology
• Sports Science
• Biomechanics

Background:

• Unilateral resistance training is often used when bilateral training is not feasible.
• Understanding optimal set configurations for unilateral training is important for maximizing performance gains.
• Previous research has not conclusively determined the best set configuration for unilateral training effects on untrained limbs.

Purpose of the Study:

• To investigate the impact of different set configurations in unilateral knee extension resistance training.
• To compare the effects of traditional training (TTG) versus rest-redistribution training (RRG) on untrained knee extensor performance.
• To assess changes in maximal voluntary force and related performance metrics.

Main Methods:

• Thirty-five participants were divided into TTG, RRG, and control groups.
• Both training groups performed knee extensions twice weekly using a 10-repetition maximum (RM) load.
• TTG used traditional sets (e.g., 4 sets of 8 reps with 3 min rest), while RRG used redistributed rest (32 reps with 17.4s rest).

Main Results:

• The untrained leg's 1-repetition maximum (1RM) significantly increased only in the TTG group (10.3%).
• Both TTG and RRG groups showed improvements in the trained leg's 1RM, maximum propulsive power (MPP), and number of repetitions with 10RM load (N10RM).
• No significant changes were observed in muscle thickness (MT) or pennation angle (PA) in either leg.

Conclusions:

• Traditional set configurations are recommended for unilateral resistance training to enhance maximal voluntary force in the untrained leg.
• This approach is particularly beneficial when bilateral exercises are contraindicated.
• Rest-redistribution set configurations may not yield the same benefits for untrained limb strength development.