Overhead throwing biomechanics in cricketers: The effect of a run-up approach.

Overhead throwing by cricketers when fielding with different approaches has been described using two-dimensional analysis. Currently, the three-dimensional kinematic and kinetic characteristics of an overhead throw performed by cricketers following a run-up are unknown. Fifteen South African cricketers performed six overhead throws, from a stationary position and with a run-up over 15-20 m prior to fielding a ball, respectively. Kinematic data and ground reaction forces were collected throughout the throwing trials. Joint kinetics were calculated using inverse dynamics. An independent -test or Mann-Whitney -test was used to determine joint kinetic differences between throwing approaches. Differences between the kinematic waveforms for stationary and run-up throwing approaches were assessed using one-dimensional statistical parametric mapping ANOVA ( < 0.05). The shoulder, elbow and thoraco-lumbar joints displayed similar kinematics between throwing approaches The run-up approach displayed increased hip flexion between 0-34% and 57-100% ((1, 28) = 6.726;  = 0.01) of the throwing cycle; and lumbo-pelvic flexion between 57 and 65% ((1, 28) = 6.823;  = 0.02) of the throwing cycle; greater shoulder compression ((1, 28) = 1.036;  = 0.02) and posterior force ((1, 28) = 1.052;  = 0.009) at maximum external rotation; yet less superior shoulder force ((1, 28) = 1.744;  = 0.005) and elbow compression ((1, 28) = 4.331;  = 0.03), superior ((1, 28) = 1.212;  = 0.002) and medial ((1, 28) = 1.370;  = 0.03) elbow forces at ball release, when compared to a stationary position. Cricketers maintain similar upper limb kinematics between overhead throwing approaches. However, throwing with a run-up approximately doubles the forces exerted on the shoulder at maximum external rotation, which is most likely caused by the greater dominant hip and lumbo-pelvic flexion noted. This may amplify the potential risk for shoulder injury when throwing.Throwing arm motion is similar irrespective of the approach used by cricketers to throw.Throwing with a run-up produced increased angles of lumbo-pelvic and dominant hip flexion in various phases of the throwing cycle.Throwing with a run-up resulted in greater shoulder compression and posterior force at maximum external rotation.