Jack of all trades, master of none. A classic example of how doing and focusing on too many different things generally leads to suboptimal results in all of them. This is true, in general, when talking about strength training. Clients often have a hard time foregoing other physical activity in pursuit of getting stronger in the short term (first 3 months or so). Not only do they want to train for strength 3 days per week, they also want to keep doing their running, Crossfit, and recreational soccer games (I know the example is a bit extreme, but it’s not entirely unheard of). Strength and endurance compete for resources when the body is adapting. This isn’t black and white, but it’s usually easy to see when a person is doing too much. Someone who adds in some low-intensity biking to their workout (20-30 minutes) likely won’t be derailed from their strength training program (and may actually benefit given other contextual factors). The person who adds 3 days of Crossfit onto a 3-day strength program will likely see suboptimal returns for both.
In exercise science this is called the interference effect, and there are a few ways we can reduce its impact. The first and easiest is simply to focus on developing your strength first (if you’re a novice, the starting strength novice progression is our preferred approach). If you’re not a novice or need to have some type of conditioning in the program, choose variations that limit the amount of eccentric loading, with minimal skill required. Riding a bike, or pushing a weighted sled are great options because they don’t require much skill and minimize the amount of soreness you’ll likely develop, which could hinder your development on the main movements. Jumping rope, swinging a kettlebell, and sprinting would be less optimal because there are a high skill component and more eccentric damage that could interfere with your ability to train productively next session. Moreover, the benefit you get from these modes of conditioning is not uniquely better than biking or sled pushing. The cost doesn’t outweigh the benefit. The takeaway from this post is, as we’ve said before: develop a base of strength with minimal interference from other physical stimuli. If necessary, program in some conditioning, preferably using a tool that keeps it simple and doesn’t negatively affect your progress on the main lifts.