In an acute bout of resistance exercise, you lift a weight that is 40% of your 1RM for a warmup set, then after resting for a few minutes you lift a weight that is 70% of your 1RM for a training set. How does your muscle produce the greater force needed for the training set? In a final training set, you lift a weight that is 95% of your 1RM. How does the muscle produce the greater force needed for this final set?