RELATIONSHIP BETWEEN KINEMATICS OF LATERAL TRUNK INCLINATION DURING JUMP FLIGHT AND KNEE VALGUS AFTER LANDING

¹Rehabilitaion College Shimane, Physical Therapy, Hamada city, Japan

Background: Female athletes with anterior cruciate ligament (ACL) injuries are considered to exhibit characteristic behavior during jump landings. The lateral trunk inclination to the supporting legs contributes to knee valgus moment after landing, increasing the risk of ACL injury (Hewett et al.2009). Previous studies have focused on trunk movements at the landing phase, and few studies of trunk movements before landing exist. Understanding pre-landing trunk movements and post-landing trunk and knee joint movements provides additional information regarding ACL preventive training.

Purpose: This study aimed to investigate trunk inclination in flight and after landing and to determine the relationships between them. Moreover, it aimed to quantify the effects of gender differences.

Methods: This study included 20 healthy males and females (10 people each). All subjects jumped forward (50% of height distance) and performed a single-leg landing with their nondominant leg. The height of the jump was specified as 30 cm. The lateral inclination of the trunk and the movement of the knee valgus angle were measured using a three-dimensional motion analysis device Myomotion (Noraxon). The lateral trunk inclination during flight was normalized to 100% from takeoff to landing (toe touchdown phase). The variables after landing included the lateral trunk inclination and the knee valgus angle at the toe touchdown phase and the maximum values after landing. The lateral trunk inclination was compared using a one-way analysis of variance (takeoff, toe touchdown phase, maximum values). The correlation between lateral trunk inclination and knee valgus was confirmed by the Pearson product–moment correlation coefficient. The significance level was set at an alpha level of 0.05.

Results: Both males and females had a lateral trunk inclination to the left during takeoff, although females were larger than males (male; 3.0±3.7°, female; 6.1±3.1°p<.05). Lateral trunk inclination during flight showed gender differences. Females slanted more than males throughout the flight. For males, the lateral trunk inclination decreased as the flight progressed, while for females, it increased again at 47.0±10.6% flight time (V-shaped change). Females had greater lateral trunk inclination both at toe touchdown phase (male; -2.5±3.5°, female; 4.8±2.7°p<.05) and maximum values (male; 3.5±5.4°, female; 4.8±2.7°p<.05). The lateral trunk inclination at takeoff was significantly correlated with the toe touchdown phase and the maximum values after landing (both sexes).
Knee valgus angles were greater in females than in males, both at toe touchdown phase (male; -5.3±1.9°, female; 4.5±5.6°p<.05) and maximum values (male; -1.4±0.9°, female; 7.2±4.2°p<.05). Males were significantly associated with lateral trunk inclination at takeoff and knee valgus angle after landing, while females were not.

Conclusions: Lateral trunk inclination occurred during takeoff and was related to post-landing posture. When performing a jump landing operation in ACL damage prevention training, teaching the takeoff attitude is also necessary.

Implications: We were able to provide a new perspective in the ACL preventive training.

Funding acknowledgements: This study is not funded.

Keywords:
Anterior cruciate ligament
Jump
Trunk movements

Topics:
Sport & sports injuries
Musculoskeletal: lower limb
Musculoskeletal

Did this work require ethics approval? Yes

Institution: Rehabilitaion College Shimane

Committee: Rehabilitaion College Shimane Ethics committee

Ethics number: 20210101