Does Improved Aerobic Fitness Reduce Fatigue During Weight Lifting?
Title: Maximum Number of Repetitions, Total Weight Lifting and Neuromuscular Fatigue in Individuals with Different Training Backgrounds
Authors: Panissa et al
Journal: Journal of Biological Sport (2013; 30:131-136)
Objective: To evaluate the performance, as well as neuromuscular activity, in a strength task in subjects with different training backgrounds.
Neuromuscular fatigue is defined as “transient decrease in muscular performance usually seen as a failure to maintain or develop a certain expected force or power.” Fatigue can be peripheral, originating from the muscle fibers or central, originating from a reduction in motor unit activation and/or fire rate.
Neuromuscular fatigue can be evaluated using electromyography, which is a technique that measures the electrical activity of muscles during various activities, including exercise and sport (and is commonly used in medicine for diagnosing nerve and muscle diseases like lou gehrig's disease).
It is known that folks with different training background affects neuromuscular fatigue, such as endurance athletes, sprinters, martial arts athletes, weight lifters.
What is not known is how it affects strength tasks such as squats and other resistance training exercises.
The authors of this study sought to assess max number of repetitions and total weight lifted, as well as neuromuscular activity in folks with different training backgrounds.
There were 26 participants divided into three groups according to their training backgrounds (aerobic, strength or mixed).
They participated three sessions:
- Determination of the maximum oxygen uptake during the incremental treadmill test to exhaustion and familiarization of the evaluation of maximum strength (1RM) for the half squat
- 1RM determination
- Four sets at 80% of the 1RM, in which the maximum number of repetitions (MNR), the total weight lifted (TWL), and the electromyographic (EMG) activity were measured.
The aerobic group performed a higher maximum number repetitions than the strength group (P = 0.045).
There was no difference for the total weight lifted.
There was a negative correlation between the maximum strength and the maximum number of repetitions (r = - 0.49; P = 0.012), and a positive correlation between the ·VO2peak and the maximum number of repetitions (r = 0.50; P = 0.034).
There was no difference was found for the electromyographic parameters.
The aerobic group performed more maximum number of repetitions than the strength group in four sets at 80% of 1 rep max squat.
It is worth noting a few baseline characteristics. The aerobic group had a lower body mass index and the strength group had a greater 1 rep max.
These results do add support to the notion that aerobic individuals are more fatigue resistance than strength training individuals.
Despite this, individuals with different training backgrounds have a similar pattern of motor unit recruitment as found in the similar electromyography results.