Today we're going to go through what kind of things are going on - during weight training or general exercise. Conventional weightlifting consists of two distinct phases of movement. The concentric phase is the positive portion of the lift (i.e. the upward push on the bar during a bench press) while the eccentric phase is the negative portion of the lift (i.e. the downward lowering of the bar during a bench press). Each portion of the lift can contribute to the muscle damage seen during weight lifting as follows:
The eccentric portion of the lift is, by definition, a form of forced lengthening of the muscle. Forced lengthening with high weight loads causes microscopic tears in the small fibers that make up the muscle and the connective tissues.
Eccentric contractions tend to involve fewer muscle fibres than other contractions meaning that each individual fibre that is used to perform the action takes a huge beating - causing muscle to become physically damaged.
During the concentric portion of the lift the force is dispersed over more fibers, which tends to require much more metabolic activity. This metabolic activity leads to depletion of muscle energy stores such as ATP and muscle glycogen (carbohydrate). This depletion, while exercising, may lead to greater susceptibility to the damage seen above.
Both the physical damage caused as well as the metabolic depletion can lead to an altered cellular calcium balance during and after exercise. The amount of calcium in the cell actually increases. This excess can activate enzymes that break down cellular proteins including contractile protein. In addition, calcium can build up in the mitochondrion of the cells, thereby decreasing cellular energy production.
Because of this disruption - the body calls for help - as there are now dysfunctional muscle debris that need to be cleaned up. So after excise, fluid begins to build up in the damaged cells in order to bring immune cells, such as neutrophils and macrophages, to the site of injury. While these cells end up clearing away damaged tissue, their activity leads to the build up of free radicals. This is why anti-oxidants are so important. Free radicals may cause further muscle damage, prolonging recovery time.
Whilst this cycle of destruction and healing continues, normal muscle function such as he ability to take up and store carbohydrates, is compromised. The result is a prolonged recovery of muscle energy, further delaying full healing.
Stiffness after training / exerciseDuring conventional weightlifting, muscle force production (strength) is diminished for at least one to three days after the damage has occurred. This loss of strength, which may take seven to 14 days to recover, is most likely due to several factors including the disruption of muscle calcium balance and energy production, the poor recovery of muscle energy during this period and the decrease in muscle protein content. In addition, this loss of strength can cause you to feel like a 90-pound weakling for several days after exercise.
Muscle swelling, as a result of fluid accumulation and immune cell delivery, occurs almost immediately after exercise. This swelling typically lasts three to four days, but may take as many as seven to subside. It's generally joined by muscle stiffness, decreased range of motion and an inability to comb your hair - if you just trained arms.
Everyone's favorite, delayed onset muscle soreness (DOMS), typically lasts from two to four days after exercise and is mostly gone within five. This soreness may come as a result of both swelling and stiffness, but some scientists now think that biochemical changes in the muscle may increase nerve sensitivity, leading to muscle pain.
Importance of recovery timeIn weight training and exercise, recovery time you may now realise is JUST as important as the actual exercise it self. Without giving your body a chance to recover, you are not giving your muscles a chance to grow stronger.
After seven to 14 days, the muscle damage stops, the immune system does it's job, muscle energy is replenished, and the muscle fibers are built back up bigger and stronger than before. The only way to improve muscle size and muscle strength is to ow adequate recovery time between workouts for the same muscle groups.
Without adequate recovery of calcium balance, muscle energy, and muscle protein content, your muscle force will be lower with each subsequent workout. In a nutshell, you'll going to grow progressively weaker. So much for getting stronger. In addition, unless you wait until full structural recovery occurs, you will simply be destroying the new muscle tissue being formed to replace the damaged tissue. And this is no way to get bigger.
How long should I wait between workouts?So how long should you wait between workouts? Tt appears that when doing intense weightlifting, a seven-day recovery period would be a good starting point. However, individuals may vary. Of course, certain recovery techniques may speed up healing.
Signs when you are ready to begin training again...
- muscle soreness is completely gone.
- full range of motion has returned.
- muscle strength is better than it was during the previous workout.
- muscle swelling has gone down. (You'll have to measure your relaxed muscle circumference before training to know when it has returned to normal.)
In Part 2b, I will look at whether prolonged recovery time - or not doing any exercise / weigh training for a while at all will lead to "detraining" e.g. losing muscle mass or strength.