Core Connection and Injury Prevention in Mae Geri

This submission is a practitioner's accepted godan examination research paper. A works cited will be provided if requested.

“To perform any kind of heavy physical work, concentration of strength is necessary”(Nishiyama and Brown). It is based on this concept that all karate-ka should exert their power: to concentrate and coordinate the strength and necessary body muscles to perform a given technique. This is exponentially important for mae geri as the practitioner is balancing on one leg while executing the technique. In the following pages mae geri and its relationship to core connection and injury will be examined. Without correct core connection, mae geri is not effective and may even cause injury to the practitioner.

The core, or lumbopelvic-hip complex, is defined as the lumbar spine, the pelvis, the hip joints and the active and passive structures that either produce or restrict movement of these segments (Willson et al.). Theses structures include the upper, lower and side abdominal muscles, the pelvic floor, and the gluteal muscles. In essence, these muscle groups work together to form a corset-like stabilization on the center of the body and the backbone (Huxel- Bliven and Anderson). Before any movement in the leg for mae geri the core is the site of the initial activity. The central nervous system sends signals to the deepest abdominals to initiate core engagement. While the body naturally readies for movement by doing this it is a considered a passive movement which not reliable on its own (Willson et al.).To have stability in the core and trunk of the body during mae geri, the practitioner must actively support the core through abdominal muscle contraction and correct posture by aligning the trunk. The passive movement along with the active moments in the abdominals and the legs make for an effective and powerful technique. This idea supports the concentration and coordination of strength as described by Master Nishiyama when he wrote: “hips first, then the hands and the feet last.” I would like to suggest that we must first activate our core, then move the hips, hands then feet.

When the practitioner is ready to perform mae geri, they must first start from a position of good posture. Whether standing in shazen tai or in a stance, their lumbar spine, pelvis and hips must all be in one line. Next, the karate-ka must activate their core by keeping a small amount of tension in their abdominal wall, especially the lower abdomen (tanden). The practitioner will not be able to properly activate the abdominals if their posture is not correct. While keeping correct posture and tension, lift one leg, bent at a 90 degree angle to about hip height (mae geri chudan). As the leg is raised, the abs should compress as if they are being squeezed like an accordion. This is where the technique becomes vulnerable if not done correctly. A common posture problem in this position is disengaging the pelvis from trunk alignment. If the trunk is not aligned and the abs are not compressed or actively engaged, the practitioner will have poor posture and likely lose their balance. Once the kicking leg is at a 90 degree position, extend the ankle and the foot of the kicking leg toward the target. The knee should act as a hinge opening up the technique. As the leg is being extended toward the target, the student should continue to keep the core compressed as well as keep the proper alignment between the spine, pelvis and hips. At full leg extension, the shoulders, hips, and knee of the support leg should all be in one plane. When the mae geri hits the target, the practitioner “should exert sufficient strength in the lower abdomen, tanden, at the precise moment that the technique is applied” (Funakoshi, p 213). If mae geri is effective, it should strike the target and transfer the power from the muscle contractions into the target while maintaining postural integrity. If it is ineffective, the power will not be transferred into the target but recoiled back from the target into the karate-ka. The recoiled power causes the karate player to “bounce” back after making contact. When a practitioner hits a target and their body recoils, it is due to a deviation in their posture or core connection. To test the effectiveness of mae geri, or any karate technique, it is important to strike a sturdy surface such as a heavy bag or makiwara.

With oi mae geri, or lunging front kick, the concepts remain the same. Before movement can be started, there must be a stable foundation: correct posture and a strong stance. The core should compress as the hips advance the kicking leg forward. The support leg and both hips should be aligned with the pelvis and the spine. This is paramount, especially with oi mae geri. As the knee opens up the leg for the kick, the abdominals should increase in tension and the trunk should be in one line. The hips should be in a full face position, heading toward the target. The core must continually adjust to maintain correct posture during the changing positions of oi mae geri. The constant adjusting and work of the trunk requires strength and endurance from these muscle groups. When oi mae geri reaches the apex, the practitioner should exert great strength through the tanden just before snapping the leg back and landing in stance. (Funakoshi, p 213) Again, the effectiveness of oi mae geri should be regularly tested by hitting substantial targets.

The lower extremities rely on the core muscles’ contraction before the onset of movement (Willson et ad.). Core muscle function and endurance has a direct relationship to the function of the the ankle and the knee. Deficiencies in core strength puts the athlete at risk for injury. Relationships have been found that show diminished capacity in the abdominals and the gluteal muscles contribute to lower back pain, knee pain and injury, and ankle sprains (Willson et al.). In a study examining hip strength in females who complained of knee pain, the subjects demonstrated a decreased ability to move and rotate their hips compared to their healthy counterparts. The authors of the study, Ireland, Willson, Ballantyne and Davis, suggest that the weakness in their hips may contribute to inability to resist knee buckling, especially when balancing on one leg. The hips are load transfer muscles with direct pelvic and lumbar spine attachments. Unstable hips compromise the pelvis and the spine and thus limiting the control for functional lower extremity movements. Mae geri relies on balance, coordination and strong legs, knees and ankles. The core directs the path in which the lower extremities should follow. Without a strong core, the knees have a tendency to adduct, or cave in toward the center of the body, creating instability and increased injury risk. Knee adductiton creates unnatural stress on the knee and ankle which also increases the likelihood for injury. After this study, the subjects did a core strengthening program and within 6 weeks, and the majority of the injured population had returned back to their lives pain free. While the core of the athletes were unstable, through regular core activities, they were able to increase their strength and thus eliminate pain and return to their sport.

Trunk muscles, or the abdominals, and the gluteus muscle group should be regularly exercised and strengthened parts of the body during karate training. A few repetitions of core drills at the beginning of a session for senior belts is always a good idea. When a new students begins training, it may be necessary to provide core strengthening activities and drills during their training period. Whether the karate-ka is a veteran or new to karate training, the instructor should examine their core stability. Weakness in stability can be observed in poor posture, poor balance, and pre existing lower back and lower extremity injuries. Deficiencies in core endurance, which is needed for prolonged stabilization in oi mae geri, is likely to be apparent when the karate player begins to show signs of fatigue. It is ideal for the exercises to include all of the core muscle groups as well as incorporating stabilizing, balance, jump training and strength activities. For example the training could be as follows, respectively: planks, single leg stands, zig zag jumping, and lunges. These exercises should be tailored to the ability of the student. As the student advances, so too should the exercises. This practice has many benefits: it enhances the awareness of the core, strengthens the core, and helps to prevent injury.

Effective karate techniques all follow the same basic path. First the abs and tanden must be activated, then movement of the hips then hands and feet follow. The lumbopelvic hip complex stability is critical for correct posture especially when moving and using the lower extremities. In order to have a powerful mae geri, karate ka must activate the large muscles of the core, then move the hips and then lastly the smaller muscles of the leg. While this is all happening, the practitioner must keep the trunk of the body upright without contortion. If the core is engaged and the trunk of the body are in one line, the practitioner should be able to perform an effective kick. Without core stability, the karate player subjects themselves to possible back, knee and ankle injury. Instructors must stress the importance of the core and its value to the student. Through daily core exercises instructors and students alike can achieve and maintain core stability which in turn will make their karate more powerful.