Strong glutes are crucial for proper function and maximum athletic performance. Many injuries and pains are attributed to dysfunction or even atrophy of the glutes.
If a reduced activation or complete inhibition of the glutes happens, other muscle groups compensate and get overused. Over time, many problems such as lower back issues, knee pain or ankle sprains may happen.
It works in reverse as well. For example, if you sprain your ankle and don't perform correct rehabilitation, you may alter your body movement, such as walking or running gait, your stance, or posture. This will add even more to the imbalances and glute inhibition and result in a greater loss of function.
The glutes consist of 3 muscles: gluteus maximus, gluteus medius, and gluteus minimus. They extend the hip and trunk and rotate the hip externally.
For your glutes to perform optimally when moving on the tennis court, all the surrounding muscles need to be functional, strong, and flexible.
If your hamstrings, hip flexors, TFL (tensor fascia latae), adductors, and lower back erectors are too tight or weak, then different compensation will happen and possibly cause even further inhibition of your glutes, and therefore more compensation of surrounding muscles.
This vicious circle needs to be broken with concentrated glute isolation training, and then gradually introducing movements that are more functional and tennis specific.
For a tennis player, correct posture and optimal alignment are crucial because they absorb the shocks occured during running on the court, and help transfer the forces through the kinetic chain during your shots.
Optimal posture makes your movement more fluid and efficient with less stress on your joints, you won't fatigue as fast, and you will have less chance to sustain overuse injuries.
If you are a student or have a typical 9-to-5 job, you probably sit quite a lot. In a seated position, your torso remains in a flexed position relative to the upper leg for extended periods, which can lead to increased tension and shortening of the hip flexor muscles.