Fig 1.
Examples of muscle cross-sectional areas (CSAs) in magnetic resonance (MR) images.
RA: rectus abdominis, OB: internal and external obliques and transversus abdominis, PM: psoas major, QL: quadratus lumborum, ES: erector spinae and multifidus, IL: iliacus, Gmax: gluteus maximus, Gmed: gluteus medius and minimus.
Table 1.
Comparisons of the cross-sectional areas (CSAs) of trunk and gluteus muscles and subcutaneous fat between long jumpers and untrained men.
Table 2.
Comparisons of the cross-sectional areas (CSAs) of trunk and gluteus muscles between takeoff and free leg sides in long jumpers.
Fig 2.
The relationship between the relative cross-sectional area (CSA) of the rectus abdominis (RA) of takeoff leg side and personal best record for the long jump.
The P value was corrected by the false discovery rate method [22].
Table 3.
Simple correlation coefficients of the cross-sectional areas (CSAs) of trunk and gluteus muscles and subcutaneous fat and 100-m sprint time with long jump distance.
Fig 3.
The relationship between the predicted and personal best records of the long jump.
The predicted record was obtained via stepwise multiple regression analysis using the personal best record for 100-m sprint and the relative cross-sectional areas of the rectus abdominis and iliacus of takeoff leg side (standard error of estimate = 22.6 cm, adjusted R2 = 0.763). The solid line is an identical line.
Fig 4.
Schematic illustrations of the body during takeoff (a) and the optimal landing position (b). a: grey and dark arrows indicate the line of action of ground reaction force and the compression of the lumbar spine along its long axis, respectively. b: the optimal landing position is one with the hips fully flexed and the trunk well forward over the legs [25].