Kinetic Chain Efficiency & Importance of Flexibility Training by Phillip Halfmann

Optimizing kinetic chain efficiency can be accomplished by making the athlete very balanced with his/her strength so that the joints function properly, which can be accomplished by enhancing range of motion (ROM) via flexibility training. Think of the body as a structure similar to that of a house. In order for the house to be well constructed the walls and connecting factors (e.g. beams) need to be symmetrical and well supported just like the skeleton.

Unfortunately, the most underrated – and underemphasised - component of most training programs is flexibility. The reason being is that the tangible outcomes are tough to quantify. For instance, when one engages in flexibility training, is there a direct gain in size or speed? No, but flexibility affects all the training components such as speed and power indirectly because flexibility is one of the factors limiting the athlete’s ability to develop power. For example, stride length impacts running and jumping economy (how efficiently one moves on the court), thereby affecting the amount of energy needed to move on the court. Therefore, flexibility does affect speed and power, but indirectly.

Many tennis players have muscular imbalances, especially at the shoulder joint where the force producing shoulder is more muscular and less flexible than the non-dominant shoulder. This becomes evident when one takes a closer look at the shoulder blades, which are “uneven”, causing postural imbalance. Also, muscular imbalance of the trunk and hip musculature can cause severe problems because, for instance, the athlete can have tightness on one side due to agitation (contracture) which can cause ¼ inch limb length discrepancy, which matters with respects to the kinetic chain (transfer of energy), where unevenness  can lead to back pain or knee pain.

Good flexibility reduces tension, produces muscle relaxation and aids in recovery. More specifically, myofascial deformation occurs when the fascia’s tension capabilities are corrupted.

When that happens the fascia doesn’t have the elastic properties and the tissue shortens causing imbalance. When one uses static and dynamic stretching exercises regularly in the training program, the muscles will become more pliable and the athlete will not experience shortening of the muscle in certain areas thereby correcting imbalances. Since muscles (tendons) connect bones with each other, poor flexibility causes problems. If the muscles are short, the bones will consequently be closer together but if the bones are closer together movement at the joint will be limited (e.g. feet will turn inward during squats – foot position will be influenced due to instability and/or muscle tightness [in abductors pulling on femur].

Flexibility is also a component of recovery. If you static stretch well after a long match or tough practice, muscle soreness will be reduced to a large extent and this will allow the athlete to play/practice the next day instead of resting. 

Warming up and stretching the muscle tissue reduces the risk of injury and increases performance potential. Subsequently, good flexibility positively affects movement range of the respective joints as well as overall kinetic energy transfer efficiency. The movement range of the joints impacts one’s speed developing capabilities because flexibility can limit the ability of the athlete to lengthen his/her stride. Most athletes’ stride length is compromised by loss of dynamic stability due to locomotion (the loss and regain of stability). The goal is to maintain dynamic equilibrium, which can only be accomplished when the centre of gravity remains within the base of support. Therefore, if stride length shortens, the base of support will decrease, which makes it more difficult to maintain the centre of mass over the base of support, making it more difficult to maintain dynamic stability. Stride length is affected, amongst other things, by the flexibility of the hamstrings. When the athlete has tightness in the hamstrings, the legs cannot extend out all the way, which decreases the distance one covers with each step and this will limit overall speed. Also, if the athlete experiences tightness or imbalance in the gluteals (buttocks) and hip flexors, he/she can’t change the pelvic position as it relates to the spine and he/she will experience dynamic instability and inefficiency in energy transfer.

In addition to the aforementioned, flexibility also plays an important role in overall joint health because it influences the integrity of the joints. Many former professional athletes suffer from osteoarthritis, which is the degeneration of hyaline cartilage (e.g. knee joint); more specifically, the breakage and loss of cartilage, which causes severe joint pain. Since joint health is related to compression within the joint as well as proper biomechanics, the use of weight-bearing activities that improve joint alignment while properly modulating the pull of muscle and connective tissues on a given joint is essential. If alignment is compromised, any repetitive motions seen in the sport of tennis can cause friction and erosion of the cartilage will occur, which can cause pain and negatively affects mobility and function. If the joint is balanced and loaded properly, integrity of the joint capsule itself will be enhanced along with all associated musculature and connective structures.  

If you are unfamiliar with how to properly perform various stretching and resistance training exercises or want to have more background information on how stretching and weightlifting minimize the risk of injuries, increase your range of motion and therefore enhance your power potential and ultimately your overall on-court performance, ask your personal trainer or buy a good book. We recommend „Advanced Concepts of Strength & Conditioning for Tennis“ by the same author.

High Knee Pull w. Dorsi Flexion
1.     Take a step and raise the left knee towards the chest
2.     Grab your leg with both hands just below the knee
3.     Pull knee as close to your chest as possible
4.     Hold the knee for 1 second
5.     Release the left knee
6.   Take a step and raise the right knee and repeat

Forward Lunge & Ankle Reach
1.     Look forward at all times
2.     Take a large step out with the left leg
3.     Drop right knee towards the ground in a controlled fashion until both knees are at 90˚
4.     Rotate the torso all the way to the right and touch/reach the ankle of the right foot
5.     Keep weight on forward heel
6.   Stand up and progress into next lunge now rotating and touching towards the left side

Emphasising kinetic chain efficiency, meaning how effectively energy can be transferred throughout the body, makes sense during tennis conditioning because the risk for injury can be significantly reduced and power output optimized since no energy is being “wasted” during sport-specific actions (e.g. the serve).