When muscle fibers are placed under greater than normal amounts of stress they will experience microscopic tearing/tissue damage. We call this muscle damage. Muscle damage occurs after resistance training and can range from very minimal to severe based on the stimulus of the training session. The greater the damage, the longer it takes to achieve strength recovery. Strength recovery refers to the time it takes for a muscle to reach the level of pre-workout strength. This will help you understand how different workouts affect muscle damage and how to deal with it.
An exercise such as pressing a kettlebell overhead, will cause damage to the muscle fibers involved in that movement as they are experiencing resistance during contraction of the muscle. The amount of muscle damage, however, is dependent on several variables. Within your workout, these variables include intensity, volume, and exercise unfamiliarity. The greater these variables are the greater the stress on the muscle.
Intensity can come in several forms. For our purposes we will address intensity as mechanical tension. Mechanical tension is simply the amount of tension required to perform a single rep. This boils down to the resistance that is being used. There is more tension required to lift a 48kg kettlebell than to lift a 20kg kettlebell. As resistance increases the number of muscle fibers recruited increases, and as a result fatigue occurs sooner. Muscles worked to fatigue or “failure” experience an increase in post workout muscle damage.
On the same note, greater volume ( number of reps) also causes an increase in muscle fiber recruitment and metabolic stress, which refers to energy production within a muscle. As exercise volume increases, more energy is required to produce contraction resulting in greater stress at the muscular level. At higher volumes you will recognize this as a “burn” or “pump”.
Exercise unfamiliarity will also play a role in muscle damage. The less familiar you are with a movement the more likely it is to produce higher levels of muscle damage and therefore require more time to recover. You may experience this when you begin a new program or try a new exercise and feel an increase in soreness the following day or two. This is a common response to a muscle being loaded with more tension or volume that it is accustomed to, but damage will be reduced as the exercise becomes more familiar.
So how do I deal with muscle damage? This is the easy part. REST. It is crucial that you allow muscle fibers to rest for 24-72 hours between workouts. Base your rest on the variables we discussed. If you train deadlift on Monday with heavy weight and 30+ reps, you should wait until Wednesday or better yet Thursday before another heavy deadlift to allow the muscle groups involved to properly recover. Now say the weight decreases but the volume increases. Even though you are using light weight, the higher repetitions and working close to muscular fatigue/failure will produce a great deal of muscle damage and require approximately 2 days of recovery before returning to pre-workout strength levels. It probably sounds like I’m telling you to only train 2 times per week and do nothing for the other 5. I’m not. What I am suggesting is adjusting weight, and number of reps depending on the day. Knowing that you need recovery, on days between heavy and/or high volume training, work on the skills that compliment the bigger/heavier lifts and high rep workouts. Keep your weight and reps low to moderate while incorporating soft tissue work like foam rolling, static stretching, and joint mobility movements into your workout. You can still train hard, but instead of chasing a one rep max or curling dumbbells until your biceps burst, focus on the integrity of your lifts. Practice mastering technique and better control and see how it improves your training.
It is important to to understand how your body is reacting to your training program. Understanding when and how to recover will allow continued improvement while avoiding injury or overtraining. If you keep laying down layer upon layer of damaged muscle without taking a step back to assess and recover you will likely burn out and get injured. Full recovery + more efficient training = more success in less time.