Coordination of segments in the vertical jump.

Three general patterns of segmental coordination (i.e., sequential [SEQ], simultaneous [SIM], and modified simultaneous [MSIM]) have been hypothesized for jumping. The purposes of this study were to describe the pattern of segmental coordination used in vertical jumping and to determine if skilled jumpers displayed distinguishing patterns of coordination. Maximum vertical jumps were performed in the counter movement (CMJ) and static jump (SJ) conditions by a heterogeneous group of 20 lean, adult subjects (AS). Smoothed, digitized film records provided the data for four segments: head-arms-trunk, trunk, thighs, and shanks. For each segment the phase of positive contribution was considered to begin with initiation of extension and end with maximum angular velocity. Bisegmental and multisegmental variables were defined to assess the extent of simultaneity. Skill was determined by the effective integration of the legs (ratio of peak upward velocity of CMJ and SJ) and by the use of stored elastic energy. Although 13 AS had MSIM patterns, the amount of flexion was small (less than or equal to 1 degree) so these AS were reclassified. With multisegmental analyses the number of AS with SIM patterns ranged from 13 to 17; about half the time was SIM. Using bisegmental analyses all 20 AS had SIM patterns; about three-fourths of the time was SIM. Skilled AS initiated extension and reached maximum velocity of the segments in proximal to distal order and with very small delays between adjacent segments.