The Joint Mechanical Function and Control of the Front Leg During Cricket Fast Bowling: A 3D Motion Analysis Study.

Cricket fast bowlers rely on the front leg as a mechanical lever during front foot contact, yet the underlying mechanisms that govern front leg behaviour remain unclear. This study examined front leg mechanics in 18 junior fast bowlers (17.2 ± 1.7 years) using a 14-camera 3D motion capture system and force platforms. Joint power and angular impulse analyses were performed to quantify hip and knee extension-flexion mechanics from front foot contact to ball release, enabling the classification of joint function as active (concentric), controlled (eccentric), or negligible. Power and angular impulse profiles revealed that front leg motion was dominated by controlled (eccentric) power at both the hip and knee, indicating that the regulation of knee angle occurred primarily through eccentric braking rather than concentric quadriceps extension. These findings suggest that achieving a "braced leg" position via isolated knee extensor strengthening may be ineffective. To evaluate whether kinematics and anthropometry contributed to performance, a multiple linear regression model was used. Run-up speed at back foot contact emerged as the strongest predictor of ball speed, whereas knee angle at front foot contact showed only a small and non-significant effect. Overall, the results indicate that front leg behaviour reflects coordinated whole-body dynamics, and performance interventions should prioritise momentum generation and timing across the kinetic chain rather than isolated joint actions.