Optimizing Youth Soccer Performance: Considerations for Injury Prevention and Recovery

Soccer is considered a high-intensity sport with intermittent high speed, high power, and agility that requires optimizing different athletic abilities, including sprinting, jumping, abrupt stopping, and changing direction. These physical demands generate high levels of injury risk for the core and lower limb muscles.

During intense soccer actions, metabolites accumulate in the muscles. This can lead to muscle fatigue and soreness. Proper recovery strategies can help clear these metabolites from the muscles more efficiently. To achieve that goal, we should understand the mechanisms that cause fatigue and soreness from the perspective of a youth coach rather than from a medical perspective.

Prevention over recovery:

It is always better to prevent damage than to deal with its consequences. In this sense, the best method is through physical conditioning, always paying attention to strength training for preventing injuries, considering the importance of including an eccentric component to the training routine, and the activation and training of all muscles.

Why do we need to consider recovery?

The scientific consensus is that during intense actions, metabolites accumulate, muscle fiber experiences glycogen depletion, and the player experiences exercise-induced muscle damage (EIMD). Many coaches emphasize dehydration, but most likely, only when playing in higher temperatures will hydration be an issue.

Game fatigue that lasts for several days lowers the player's capabilities in subsequent games, and we must consider an approach to help the players. From a training perspective, EIMD and glycogen depletion are our primary concerns.

Glycogen depletion: When the body experiences glycogen depletion, it will take about 24 hours to convert food and replace glycogen. It is understood that carb-containing foods will help replenish glycogen the most efficiently.

When food is digested, glucose is created. The pancreas recognizes this and produces insulin, a hormone that regulates glucose in the bloodstream. Any glucose not used then is directed to the liver to be stored as glycogen.

If, during a game, a player depletes glucose and glycogen yet does not take enough or the correct food intake, the restoring does not take place. With the continuation of exercise, the depletion goes further to the point where the player can't perform and increases the risk of serious injury.

One way that athletes store large amounts of glycogen is through carb loading. This is why carbohydrate-rich meals are consumed before a game.

Aside from the poor athletic performance that a lack of glycogen induces, a player must eat well to prevent glycogen depletion to a point where the storage keeps decreasing throughout the season to a point where serious muscle injury can occur.

Exercise-induced muscle damage (EIMD)

Exercise-induced muscle damage results in an immediate and prolonged reduction in force and power generation capacity from the muscle and increased physiological demand to overcome the discomfort.

The fundamental causes of EIMD are not clearly understood. Still, it is generally accepted that how the body consumes energy and the muscles' actions contribute to muscle damage.

During exercise, muscles can be damaged both chemically and mechanically. The chemical imbalance in the muscles results from disturbances manifesting as muscle fiber weakness. The mechanical stress comes from a mechanical load that tears the fiber and changes the permeability of the cell membranes, changing the way fluids reach the cells. These two factors (chemical and mechanical) interact, creating a complex system that is difficult to generalize and requires an individual approach to game readiness recovery.

A critical difficulty in player management is how we can measure or determine the extent of muscle damage when one does not have laboratory settings and often does not have the equipment that would allow practical determination by the youth coach or parent.

The key performance indicators manifest as prolonged loss of strength and power, which can be measured by isokinetic and isometric strength tests, sprints, and jumps.

Eccentric contraction (ECC) is said to cause the most severe muscle damage. ECC means that load is applied when a muscle is lengthening. It is forceful stretching. In the sport of soccer, there are plenty of such muscle contractions. The landing of the feet during running and jumping, the braking actions during decelerations and sharp turns, and the counteractions of the muscles while kicking the ball—all these are examples of ECC.

If not addressed during preparation and management by the player, all of these muscle actions can contribute to long-lasting damage. Studies suggest that muscle soreness lasting several days after the game is more influenced by short, intense movements such as sharp turns, acceleration, and deceleration than total work volume.

Concentric contraction (CC) is when the muscle shortens and produces power to lift something or move the body. CC uses more energy than ECC and is partly responsible for the speed and power at which a movement is executed.

Due to the interaction between different muscles and the fact that within a particular movement, ECC and CC happen, it is essential to understand and consider training and recovery regimes that encompass the benefits of all muscles. While we tend to train muscles that are critical or advantageous for the performance of the sport, and those muscles can support a large magnitude of muscle lengthening, applied force, and duration, providing the player with the speed, power, and agility to perform, the muscles we disregard may be the ones that fail, causing pain and discomfort and creating suboptimal player performance or injury.

When EIMD results in mechanical disruption of the functional muscle (not muscle tears and pulled muscles—medical attention), the flow of fluids containing ions is expected to be interrupted, and some of the muscle fibers die, resulting in inflammation. With the lack of ionic liquids in the muscle fibers, the excitation-contraction coupling fails in those fibers, and the muscle does not have its full function.

Alternatively, the failure of the excitation-contraction coupling may lead to muscle weakness, which is the root cause of EIMD mechanical disruption.

When EIMD results in mechanical disruption of functional muscle, inflammation can occur. This can lead to a loss of muscle function. Proper recovery strategies, including rest and nutrition, can help reduce inflammation and promote healing.

Inflammation is part of the adaptation process in training. It begins almost immediately after the end of exercise and may continue long after that. The goal of the development process is to manage the inflammation and limit its damaging influence on the player's development.

Scientific studies suggest that fighting training-induced inflammation during training is unnecessary, and medication is neither necessary nor advisable. However, cold therapy is encouraged, and proper attention to the potential secondary muscle injuries is significant for optimum player health and athletic development.

Recovery

Stretching after a game may provide some temporal relief. If done consistently over long periods (every game and practice), it may make the muscles more adaptive to tension at a longer length, providing a good adaptation for ECC. However, stretching does not fix disruption; hence, stiffness returns after stretching, and it is not very helpful in recovery.

An essential aspect of recovery is the restoration of energy stores, the reinstatement of glycogen reserves, and the supply of proteins to repair muscles.

A proper eating routine can enhance the synthesis that occurs in the short term. Some studies suggest a "window of opportunity" immediately after the game when carbohydrates and proteins are digested better. Healthy food can provide everything necessary to reinstate glycogen stores: proteins, fluids, and minerals.

There are some ambiguities regarding the benefit of cold-water immersion; some professional athletes consider it essential, while others prefer something like cool water or just immersion in neutral-temperature water. It is important to consider that immersion of the body in water lowers the temperature of the muscles, helping attenuate the oxidative state and neutralize its damage. The hydrostatic pressure allows the blood to flow towards the inside of the body, increasing the flushing of the metabolites from the muscles.

A combination of cold-water immersion or a cold shower with a hot shower or some time in a sauna is beneficial because the change in temperature results in muscle pumping and increases metabolism.

While massage is popular among recovery routines, there is no scientific evidence that it is beneficial other than a feel-good placebo effect. There is some assumption that massaging a muscle helps the re-alignment of disrupted muscle fiber and relieves local contraction of the muscle, providing a feel-good condition.

Active recovery the next day after the player can digest a full meal and rest (sleep) is recommended. A coach is to provide training sessions that reflect the athlete's playing time, with training routines that provide recovery for those players with accumulated playing time and strength and conditioning for those players that did not play or had reduced playing time.