Low-load Slow Movement Squat Training Increases Muscle Size and Strength but Not Power.

Area of Science:

• Exercise Physiology
• Muscle Physiology
• Sports Science

Background:

• Muscle hypertrophy and strength gains are primary goals of resistance training.
• Optimizing training protocols for both strength and power remains a key area of research.
• Low-load training offers an alternative to traditional high-load methods, but its effects on different performance metrics require clarification.

Purpose of the Study:

• To investigate the effects of slow, controlled low-load squat training (LST) on muscle size, strength, and power.
• To compare the outcomes of LST with low-load normal speed training (LN).

Main Methods:

• Healthy young men were divided into two groups: LST (50% 1-RM, 3s eccentric/concentric, no pause) and LN (50% 1-RM, 1s eccentric/concentric, 1s pause).
• Both groups completed an 8-week squat training program (3 days/week).
• Measurements included muscle thickness, isometric torque, 1-RM squat, lifting power, EMG rise rate, leg extension power, and vertical jump height.

Main Results:

• The LN group showed no significant changes in any measured variables.
• The LST group demonstrated significant increases in quadriceps femoris muscle thickness (6-10%), isometric hip extension torque (18%), and 1-RM squat (10%).
• No significant improvements were observed in isometric knee extension torque, lifting power, EMG rise rate, leg extension power, or vertical jump height in the LST group.

Conclusions:

• Low-load squat training with slow movement and tonic force generation (LST) is effective for increasing muscle size and task-specific strength.
• LST does not appear to enhance dynamic explosive power or rate of force development.
• Training protocols should be tailored based on specific goals, whether aiming for hypertrophy/strength or power development.