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最終更新日：2026/01/18
山﨑 和也
ヤマザキ カズヤ
(Kazuya Yamazaki)
講演・口頭発表等
- 発表タイトル
- 発表タイトル（英）
- Phase-Specific Force-Time Characteristics of Countermovement Jump in Japanese Elite Female Athletes Following ACL Reconstruction
- 参照URL
- 会議名
- 会議名（英）
- ASPETAR world conference 2025
- 開催地
- 開催地（英）
- Doha
- 国名
- カタール
- 概要
- 概要（英）
- INTRODUCTION Anterior cruciate ligament (ACL) injuries present a major challenge in elite sports, especially among female athletes are known to have a higher incidence and re-injury rate compared to male athletes. Countermovement jump (CMJ) assessment using dual force plates enables detailed phase-specific kinetic analysis and has become a widely adopted tool for dynamic performance evaluation, particularly during the return-to-play (RTP) process. However, most previous research on lower limb dynamic evaluation during the RTP phase has focused on male athletes or Western populations. There is a lack of data, particularly concerning elite female athletes in Asia, necessitating further accumulation of knowledge. AIM This study aimed to examine the characteristics of each phase of the force–time curve and the corresponding inter-limb asymmetry patterns during CMJ in Japanese elite female athletes 7–9 months post-ACL reconstruction (ACLR), compared with healthy elite female athletes. METHODS Nine Japanese elite female athletes aged 18 years or older who had undergone anterior cruciate ligament reconstruction (ACLR group; 240.2 ± 21.0 days post-surgery), and 141 healthy elite female athletes (Control group) performed maximal effort CMJ on dual force plates (1000 Hz). Jump height, movement time, inter-limb asymmetries in impulse during the braking and propulsive phases, rate of force development during the braking phase (braking RFD), were calculated and statistically compared between the two groups. Welch’s t-test and Cohen's d effect size were used for statistical analysis. (p<0.05) RESULTS The ACLR group exhibited lower performance metrics compared to Control group: jump height (28.1 ± 5.3 vs. 32.4 ± 4.6 cm, p = 0.04, d = -0.93), and braking RFD (4,447 ± 1,867 vs. 6,066 ± 2,039 N/s, p = 0.03, d = -0.80). No significant differences were observed between the two groups in each phase duration and inter-limb asymmetries in impulse during the braking and propulsive phases. CONCLUSIONS These results suggest that, even in female athletes approaching RTP following ACL reconstruction, not only simple outcome measures such as jump height but also detailed assessments of the braking phase are important for return-to-sport decision-making. Moreover, the results highlight the importance of incorporating deceleration-focused interventions during the rehabilitation process after ACLR. On the other hand, the absence of significant group differences in inter-limb asymmetry may be attributable to the nature of the task, which requires bilateral vertical force production; it is possible that the force output of the non-injured limb was subconsciously modulated to match that of the reconstructed limb. Therefore, a more comprehensive assessment that includes unilateral CMJ or similar tasks may be necessary to detect subtle asymmetries.
- 国際会議かどうか
- 国際会議
- 主催者
- 主催者（英）
- ASPETAR
- 講演者
- 講演者（英）
- Kazuya Yamazaki, Shuji Tanaka, Naoto Nishikawa, Moeko Akimoto, Kanae Hosaki, Miyuki Furukawa, Frederick J. Henderson, Naomi Takashima, Akira Suzuki, Yasushi Hotta, Saeko Takahashi, Ayano Tanaka, Rie Shoji, Tetsuhiko Sakamitsu, Yusuke Nishida, Kohei Nakajima, Daichi Yamashita
- 発表年月
- 2025年10月
- 招待の有無
- 会議種別
- ポスター発表
- DOI URL