Author(s): ARIYOSHI, K., Institution: OSAKA UNIVERSITY OF HEALTH AND SPORT SCIENCES, Country: JAPAN, Abstract-ID: 472

INTRODUCTION:
In badminton, forward lunges usually use a straight toe landing (STL) to prevent injury. However, in recent games, some players have used a toe-in landing (TIL) depending on the rally situation. We hypothesize that this is a new skill to cope with faster rally speeds. but its effects and mechanical burden on the body are not clear. Therefore, the purpose of this study was to compare the contact time and plantar load of STL and TIL.
METHODS:
The subjects were 10 male players (age 19.9 ± 2.1 years, height 171.3 ± 11.7 cm, weight 65.0 ± 12.0 kg) who had been playing badminton for 7 years or more. The starting position was the center of the short service line on the badminton court, the player touched the shuttlecock hanging on the court with his racket and returned to the original position. The type of attempt was STL and TIL with the leg brought forward. Each measurement was performed three times, and the value with the shortest ground contact time was adopted. The analysis items were ground contact time and plantar load force. The plantar loading force was measured using Pedar-X in-shoe pressure measurement system (Novel, USA) , and defined in areas hallux, lesser toes, medial forefoot, middle forefoot, lateral forefoot, medial midfoot, lateral midfoot and rearfoot. The ground contact time was defined as the time when any sensor had 10N or more. Statistics were compared between STL and TIL for ground contact time, plantar load/body weight, and plantar load distribution, and a paired t-test was used (p<0.05).
RESULTS:
Ground contact time was significantly faster for TIL (0.31±0.02sec) than for STL (0.36±0.02sec) (p<0.001).
The plantar load force/weight of TIL was significantly higher in hallux (p=0.045), medial forefoot (p=0.003), middle forefoot (p=0.049), and lower in lateral midfoot (p=0.028) and rearfoot (p=0.005). [ hallux: STL 1.48±0.69N/kg, TIL 2.06±0.64N/kg; lesser toes: STL 1.64±0.46N/kg, TIL 1.79±0.62N/kg; medial forefoot: STL 1.31±0.43N/kg, TIL 3.00±1.29N/kg; middle forefoot: STL 1.85±0.42N/kg, TIL 2.50±0.96N/kg; lateral forefoot: STL 1.32±0.27N/kg, TIL 1.49±0.43N/kg; medial midfoot: STL 1.13±0.37N/kg, TIL 1.45±0.62N/kg; lateral midfoot: STL 1.20±0.52N/kg, TIL 0.83±0.28N/kg; rearfoot: STL 4.43±1.59N/kg, TIL 2.45±1.09N/kg. ]
The plantar pressure distribution of TIL was significantly higher in medial forefoot (p=0.007), and lower in lateral midfoot (p=0.023) and rearfoot (p=0.002).
A similar trend was observed for force/weight and plantar pressure distribution for plantar load work.
CONCLUSION:
It was suggested that the forward lunge at B shortens the ground contact time and may speed up the movement to the next shot. It was confirmed that the ratio of the plantar load force shifts from rearfoot to medial forefoot.