2019 Volume 64 Issue 1 Pages 89-99
In sprint running, stance time and flight time influence running speed. This study investigated the relationship between flight ratio (= flight time/stance time) and the upper limbs and recovery leg during the top speed phase in sprinting. Sixteen male sprinters (age 19.3±0.6 y, height 1.74±0.06 m, weight 66.1±5.2 kg) performed maximum-effort 60-m sprints. Video data from the 43.5 to 50 m section of the sprint were collected using a high-speed camera (300 Hz). Flight ratio and vertical acceleration force of the upper limbs relative to the sternum and recovery leg relative to the hip were calculated. The data revealed a significant positive correlation between flight ratio and the relative vertical acceleration force of the forward arm, backward arm, and recovery leg at the instant of touchdown (r =.597, .546, .592). The maximum value of the relative vertical acceleration force of the forward arm, backward arm, and recovery leg during the stance phase was not associated with the flight ratio. In contrast, early appearance of the maximum value of the vertical relative acceleration force of the forward arm, backward arm, and recovery leg during the stance phase was associated with a high flight ratio (r = -.553, -.644, -.855). Multiple regression analysis revealed that the high angular velocity and low extension acceleration of the arms and recovery leg at touchdown made a significant contribution to high relative vertical acceleration. In conclusion, rapid swinging and high shortening acceleration of the arms and recovery leg can contribute to a high flight ratio by facilitating a high relative vertical acceleration force.