Overview of muscle fatigue differences between maximal eccentric and concentric resistance exercise

Area of Science:

• Exercise Physiology
• Muscle Physiology
• Sports Science

Background:

• Muscle fatigue, defined as acute strength loss, has been studied in relation to maximal eccentric (ECCmax) and concentric (CONmax) resistance exercise since the 1970s.
• Despite extensive research, a definitive conclusion regarding differences in muscle fatigue between ECCmax and CONmax exercise remains elusive.

Purpose of the Study:

• To systematically review and synthesize the methods and findings of studies comparing acute changes in muscle strength following ECCmax and CONmax resistance exercise bouts.
• To elucidate the potential disparities in muscle fatigue manifestation between eccentric and concentric contractions.

Main Methods:

• A comprehensive literature search identified 30 relevant studies investigating muscle strength changes after ECCmax and CONmax exercise.
• Studies typically involved healthy men aged 20-40 years performing 40-100 isokinetic repetitions of knee extensors or elbow flexors.
• A subset of seven studies examined muscle fatigue during coupled ECCmax-CONmax exercise, and three studies analyzed repetitions at equal relative loads.

Main Results:

• Both ECCmax and CONmax exercise induced significant strength loss, generally not exceeding 60% of baseline, indicating substantial strength preservation.
• Upper-body muscles exhibited similar strength loss after ECCmax (31.4%) and CONmax (33.6%) exercise.
• Lower-body muscles demonstrated less strength loss following ECCmax (13.3%) compared to CONmax (39.7%) exercise, suggesting enhanced fatigue resilience.

Conclusions:

• Muscle fatigue manifests differently between ECCmax and CONmax resistance exercise, particularly in the lower body.
• Factors such as muscle architecture and daily functional demands likely contribute to the greater fatigue resistance of lower-body muscles during ECCmax exercise.
• Exercise prescription for eccentric resistance training, especially for lower-body muscles, should consider their inherent resilience to fatigue compared to upper-body muscles.