Weightbearing ankle dorsiflexion range of motion and sagittal plane kinematics during single leg drop jump landing in healthy male athletes

BACKGROUND: Passive ankle dorsiflexion range of motion (DROM) measures have been identified as a risk factor for injury during landings. However, passive measurements might not be indicative of dynamic ankle movement, whereas a weightbearing ROM might be a better tool when evaluating movement. The purpose of this study was to investigate the relationship between weightbearing DROM and sagittal plane landing mechanics in a single leg drop jump task. METHODS: Seventy-three male athletes (22.1 +/- 3.9 years old, height 186.2 +/- 11 cm, and weight 100.2 +/- 21.8 kg) performed bilateral modified-lunge tasks and bilateral single leg drop jump landings while 3D kinematic data were collected. Hip, knee, and ankle joint angles were calculated at initial contact (IC) maximum knee flexion (MKF), and total excursion (TE) during a single leg drop jump landing. RESULTS: No bilateral differences in DROM and single leg landing mechanics existed. Decreased ankle DROM was correlated to decreased ankle dorsiflexion at MKF (P=0.00) and TE (P=0.00) for both dominant and non-dominant limbs. Decreased ankle DROM was also correlated to decreased knee flexion at IC (P=0.00), MKF (P=0.00), and TE (P=0.1), for both dominant and non-dominant limbs. Ankle DROM correlated to hip flexion at MKF (r=0.25) and TE (r=0.30) in the dominant limb. CONCLUSIONS: Restrictions in DROM may contribute to a stiff landing with less flexion at the ankle and knee. These findings may be useful in designing training programs aimed at increasing DROM in order to improve an athlete's landing mechanics and decrease risk of injury.