Absolutely! I explain overtraining to my clients like this: Imagine a bucket with a hole in the bottom. Think of exercise like water, and think of the water draining out of the bottom as the recovery period. It only makes sense that your body takes longer to recover from exercise than it takes TO exercise (same concept with an injury); otherwise we’d have a lot more olympic athletes! If you put water into the bucket so fast that it doesn’t have time to drain out, you’re just kidding yourself. You have to give yourself and your clients proper rest or else the benefits are diminished, and you never get anywhere. Rest intervals depend largely on the amount/intensity of training and the overall level of fitness.