Training to Failure Using Light vs. Heavy Weights
Training to Failure Using Light vs. Heavy Weights
For those of you curious to know what happens when you train to failure using light weights versus heavy weights – a recent study may have the answer you’re looking for.
In this 2015 study, researchers split 18 young men who were experienced in weight training into two groups. Both groups followed a similar weight-training program consisting of three sets of seven exercises (flat bench press, standing military press, lat pulldowns, seated cable rows, full squats, leg press and leg extensions) performed till failure (concentric). They performed this routine three times a week on non-consecutive days for 8 weeks.
The difference between groups was the load (weight) they used.
One group used a lighter load, which was approximately 30-50% of their one-rep max (1RM) for each exercise. This allowed them to perform 25-35 reps per set on each exercise before they hit failure. The other group used a heavier load, which was 70-80% of their 1RM. This allowed them to complete 8-12 reps on every set for every exercise. (Note: The load was adjusted for each exercise as needed to ensure subjects achieved failure within the target rep range.)
Before and after the study, the researchers measured the muscle thickness of the arms (biceps brachii, brachialis and triceps brachii) and the quadriceps. They also tested muscle strength on the bench press and leg press. Additionally, muscle endurance was measured on bench press by seeing how many reps the subjects could perform using 50% of their 1RM.
What they found was that there was no significant difference in muscle thickness in the arms or quads between the two groups after 8 weeks. However, those who performed sets using a heavier load had increased their strength significantly more on full squats than those using a lighter load. There was also a trend for greater increases in flat bench press with the heavier load group, but it wasn’t statistically significant. Finally, muscle endurance on bench press was significantly higher in the lighter load group when compared to the other group.
With the above in mind, I would think most of us might not be surprised that the heavier load lead to greater increases in strength and the lighter load improved endurance. However, you may be surprised to find out that muscle thickness was not significantly different between groups. While this was just one study and used well-trained individuals, it’s something to keep in mind as this knowledge may become useful when training for size, strength and/or endurance.
For more information:
Schoenfeld, BJ. et al. Effects of Low- Versus High-Load Resistance Training on Muscle Strength and Hypertrophy in Well-Trained Men. Journal of Strength and Conditioning Research. 2015. Oct;29(10):2954-63.