Fig 1.
A postero-superior view of the set position during the block start phase.
(A) Set position in the widened condition. (B) Set position in normal condition.
Fig 2.
Definition of the double-leg and single-leg stance phases during the block start phase.
The block start phase was divided into double-leg and single-leg stance phases based on the instant of rear-leg take-off. The black solid line represents the pelvis and front leg, the black dashed line represents the rear leg, and the grey line represents the other segments that were not analyzed in this study.
Fig 3.
Normalized block-induced power in widened and normal conditions.
The bold solid line indicates the mean value of normalized block-induced power in all participants, and the thin dashed lines indicate the normalized block-induced power in each participant (n = 14).
Table 1.
Mean ± SD, range and reliability of sprinting performance during the block start phase and the subsequent sprinting time in widened and normal conditions.
Fig 4.
Changes in the hip angles during the block start phase normalized with respect to time.
(A) Hip extension angles in front leg. (B) Hip extension angle in rear leg. (C) Hip abduction angle in front leg. (D) Hip abduction angle in rear leg. (E) Hip external rotation angle in front leg. (F) Hip external rotation angle in rear leg. The black and grey lines indicate the mean (bold) ± SD (thin) of the time-series data of the front and rear/swing legs in widened and normal conditions. These angles at the initial and end instants of double- and single-leg phases and at the instant when the peak value occurs were compared between the two conditions. Significant differences between the two conditions are shown as * (P < 0.05). Significant difference between the front and rear legs in widened condition are shown as † (P < 0.05) and that in normal condition are shown as § (P < 0.05). The vertical dashed line indicates the instant of rear leg take-off during the block start phase.
Fig 5.
Changes in the hip moment, angular velocity, and joint power normalized with respect to time.
(A) Hip extension moment in front leg. (B) Hip extension moment in rear leg. (C) Hip extension angular velocity in front leg. (D) Hip extension angular velocity in rear leg. (E) Hip joint power in front leg. (F) Hip joint power in rear leg. The black and grey lines indicate the mean (bold) ± SD (thin) of the time-series data of the front and rear/swing legs in widened and normal conditions. These angles at the initial and end instants of double- and single-leg phases and at the instant when the peak value occurs were compared between the two conditions. Significant differences between the two conditions are shown as * (P < 0.05). Significant difference between the front and rear legs in widened condition are shown as † (P < 0.05) and that in normal condition are shown as § (P < 0.05). The vertical dashed line indicates the instant of rear leg take-off during the block start phase.