High- and Low-Load Resistance Training

High- and Low-Load Resistance Training to Failure Result in Similar Muscular Adaptations in Untrained Young Males

The goal of this clinical trial is to learn whether low-load resistance training performed to muscle failure can produce similar increases in muscle size and strength as high-load resistance training in healthy untrained young adult males.

The main questions it aims to answer are:

Does low-load resistance training (30% of one-repetition maximum) performed to failure increase muscle strength and muscle size to a similar extent as high-load resistance training (75% of one-repetition maximum)?

Are there differences in total training volume between low-load and high-load resistance training programs performed to failure?

Researchers will compare a low-load resistance training group to a high-load resistance training group to determine whether the magnitude of changes in muscle strength and hypertrophy differs between the two approaches.

Participants will:

Be randomly assigned to either a low-load (30% 1RM) or high-load (75% 1RM) resistance training group

Perform supervised leg extension exercises to the point of voluntary muscle fatigue three times per week for 6 weeks

Complete muscle strength testing (one-repetition maximum) before and after the training period

Undergo ultrasound measurements to assess muscle thickness and cross-sectional area of thigh muscles before and after the intervention

Inclusion Criteria:

• Male sex
• Age between 18 and 28 years
• Healthy status as determined by self-report health screening
• No participation in structured resistance training or lower-limb power training within the previous 12 months
• Engaging only in recreational physical activity (no systematic lower-body resistance training)
• Willingness to maintain usual daily routines throughout the study period
• Agreement to refrain from any structured lower-body resistance training during the 6-week intervention
• Provision of written informed consent

Exclusion Criteria:

• Any current or recent musculoskeletal injury affecting lower-limb function
• History or presence of cardiovascular disease
• History or presence of metabolic disorders
• Resting hypertension (≥140/90 mmHg)
• Regular tobacco use
• Use of medications known to affect neuromuscular performance
• Inability or unwillingness to comply with the training protocol