Whether you’re lifting for size or strength, how you focus during each rep of your workouts can have a big impact on your results.
United Kingdom researchers had trained lifters do 10 reps of one-arm biceps curls on three separate occasions. During one trial, the subjects performed curls as they normally would. In another trial, they did curls while focusing on the contraction of the biceps. In a third trial, they did curls while focusing on moving the weight.
The scientists reported that when the subjects focused on the contraction while doing curls, the muscle activity of the biceps was increased by more than 20%. However, when they focused on moving the weight while performing curls, their muscle strength was increased by about 10%.
Focus is clearly critical when you are training. But you need to focus correctly based on your goals for that set.
On heavy sets, when you want to have more strength, focus on moving the weight to stay stronger. However, on lighter sets, focus on the contraction of the muscle. This will boost muscle activity of the target muscle, which will help to encourage greater growth of that muscle.