Keisuke Okubo*, Maho Nakano*, Hiroyuki Ishizuka**
Sports are receiving increasing attention in Japan ahead of the 2020 Tokyo Olympic Games. The goal of this study was to verify the effect of standard Namikoshi shiatsu therapy on sports performance.
After adequate warm-up, the test subject performed five 50-meter sprints separated by 5-minute rest intervals. The sprints were timed and photographed using a fixed camera to facilitate running posture analysis. Abdominal shiatsu, consisting of the standard 20 points on the abdomen, repeated 3 times, was applied before the initial run and during each 5-minute interval. During control testing, the subject spent the same time resting in supine position. Testing was performed on different days for shiatsu and control sessions.
On average, sprint times were shorter when shiatsu had been applied. Comparison of photographic images also showed changes in trunk rotation, knee flexion, and stride length. These results suggest that Namikoshi standard abdominal shiatsu consisting of pressure to 20 points on the abdomen may have positive effects on sprint performance.
Keywords: Shiatsu, running, sprint, abdominal region, abdominal pressure, trunk, exercise, 50m, track and field, manual therapy, angular momentum, image, rectus abdominis, external abdominal obliques, internal abdominal obliques, Olympics, Stride length, rotation, motion, ROM, joint range of motion, joints, load, track, competition, time, massage, start, dash, run, crouch start, running motion, standard Namikoshi abdominal region shiatsu
In this study, we examined the effect of standard Namikoshi 20-point abdominal shiatsu1 applied to a runner prior to running a 50- meter sprint on ankle, knee, trunk, and shoulder joint ROM, hip flexion speed, and starting hip position, and verified the accompanying changes to stride length and run time.
Measurements were taken after applying shiatsu stimulation to the test subject on August 15, with control measurements taken on August 2 when the test subject had received no shiatsu stimulation. Shiatsu stimulation consisted of standard Namikoshi 20-point abdominal shiatsu, repeated 3 times, before the initial run and during the 5-minutes rest interval prior to each of 5 runs. Adequate stretching was carried out prior to running2.
Date: August 2 and 15, 2015
Location: Komazawa Olympic Park athletic field, straight track
Played soccer from elementary school to University
Equipment: CASIO Digital Sports Stop Watch HS-70W
Imaging equipment: Sony Handycam HDR-SX420
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The short-distance running cycle can be divided into two phases: (1) the support phase (when the sole of the foot is in contact with the ground); and (2) the recovery phase (when the sole of the foot is not in contact with the ground). Phases (1) and (2) can each be further divided into three sub-phases. The (1) support phase includes (1)-1 foot strike (the period when a portion of the sole of the foot is in contact with the ground); (1)-2 mid support (The period from when the sole of the foot is in full contact with the ground, supporting the body’s weight, to immediately before the heel loses contact with the ground); and (1)-3 takeoff (the period from when the heel loses contact with the ground to when the toes leave the ground). The (2) recovery phase includes (2)-1 follow-through (the period from when the sole of the foot leaves the ground to when the sole of the foot leaves the ground to when rearward motion of the lower leg ends); (2)-2 forward swing (the period when the lower leg is moving from back to front); and (2)-3 foot descent (the period immediately prior to when the ground). Specific muscles are active during each of these phases, which may very depending on running speed. When observing the muscles active while running, the abdominal muscles are strongly active only when running 100 m at an average speed of 36km/h, as compared to 1km at an average speed of 12km/h or 16lm/h. During the running cycle, strong abdominal muscle activity is observed from (1)-2 to (2)-23.
The reason abdominal muscle activity is only observed in short-distance running is due to the strong angular momentum generated between arm swinging and the pelvis. While running, the pelvis produces rotational motion on a vertical axis, generating angular momentum around the vertical axis. Arm swinging is important for reducing trunk deflection due to this motion; in practice, the angular momentum produced by arm swinging eliminates the trunk deflection due to pelvic angular momentum. This is a distinguishing characteristic of short-distance running4.
In running there is an ideal leg trajectory. According to research conducted using a sprint training machine, leg motion effectively utilizes flexible twisting and rotation motions in the pelvis ad trunk and is also necessary to adroitly maintain balance. Also important is that this motion originates in the epigastric fossa, around the level of the upper lumbar and lower thoracic vertebrae5.
Muscles thought to be affected by abdominal region shiatsu include the muscles related to maintaining abdominal pressure (diaphragm, rectus abdominis, external abdominal obliques, internal abdominal obliques). When these abdominal wall muscles contract in coordination with the pelvic floor muscles, intra-abdominal pressure rises. It is known that increased intra abdominal pressure significantly reduces the load placed on upper and lower lumbar intervertebral discs6.
Based on the above discussion, one possible explanation for improved running performance and shorter times recorded in this study is that abdominal shiatsu resulted in more coordinated performance of muscles involved in maintaining intra abdominal pressure and improved trunk stability. It is also possible that improved response time from the start of the sprint to the first step resulted in faster running times, but analysis would be problematic at this stage.
Abdominal shiatsu does not directly affect the lower limbs, which are the focus of running. However, it may have an effect on the trunk, from where such motion originates, contributing to more ideal motion in the upper and lower limbs.
Nevertheless, many points in this study remain unclear, and it is possible that there would be no effect on middle or ling distance running times, where abdominal muscle activity is less apparent. More specialized testing and analysis is required.
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- Sakai I et al translator: Purometeus kaibogaku atorasu kaibogaku soron undokikei dai 2 ban. Igaku shoin, 2013 (in Japanese)
*Shiatsu Department, Japan Shiatsu College, **Shiatsu instructor, Japan Shiatsu College