Low-Load x High-Load Resistance Exercise: Greater Cell Swelling After a Training Session

Area of Science:

• Exercise Physiology
• Muscle Hypertrophy

Background:

• Cell swelling from resistance training (RT) is theorized to stimulate muscle anabolism.
• These anabolic effects are thought to be amplified by low-load RT protocols.

Purpose of the Study:

• To compare the acute effects of volume-equated low-load (LL) versus high-load (HL) RT protocols.
• To investigate impacts on elbow flexor muscle thickness, arm circumference, and blood lactate.

Main Methods:

• Eight resistance-trained males participated in two RT protocols: LL (50% 1RM) and HL (85% 1RM).
• Protocols involved unilateral elbow flexion, with volume equated between conditions.
• Measurements included muscle thickness, arm circumference, and blood lactate pre- and post-session.

Main Results:

• Both LL and HL RT significantly increased muscle thickness and blood lactate.
• Magnitude of increase favored LL for muscle thickness and blood lactate, though not statistically significant between conditions.
• LL training showed significant increases in total repetitions, time under tension, and training density compared to HL.

Conclusions:

• LL resistance training elicits greater acute increases in muscle thickness.
• RT protocols emphasizing longer time under tension and higher training density appear beneficial for acute cell swelling.