Too much of a good thing can be a bad thing
When faced with a dilemma related to nutrition or health – or anything else in life for that matter – I always start by looking at the issue from the perspective of an evolutionary biologist. When we stress our bodies in evolutionarily novel ways, adverse health effects tend to occur. These novel stimuli can be categorized into three categories: Too new, too much, and too little. Excessive strength training fits into two categories: Too much and too new.
Our ancient forebears were very physically active, but they obviously never performed heavy squats, deadlifts, and other similar exercises that many runners, sprinters, weight lifters, and fitness enthusiasts do today. That doesn’t mean that we shouldn’t be doing these types of exercises; however, it does imply that we should be a little cautious about how much and what types of strength training we do.
Heavy resistance exercise puts a lot of strain on the body. Our musculoskeletal systems are very adaptable, in the sense that our muscles and bones get stronger when they are stressed, something that ensures that the body is better able to perform similar activities in the future. That said, there is a limit to how much stress we can put on our bodies before they malfunction. I would argue that many gym goers who adhere to a bodybuilding-type training program, in particular those who do virtually every set to failure and completely destroy each muscle group once or twice a week, are pushing their bodies past this limit.