The influence of cricket fast bowlers’ front leg technique on peak ground reaction forces

Abstract

High ground reaction forces during the front foot contact phase of the bowling action are believed to be a major contributor to the high prevalence of lumbar stress fractures in fast bowlers. This study aimed to investigate the influence of front leg technique on peak ground reaction forces during the delivery stride. Three-dimensional kinematic data and ground reaction forces during the front foot contact phase were captured for 20 elite male fast bowlers. Eight kinematic parameters were determined for each performance, describing run-up speed and front leg technique, in addition to peak force and time to peak force in the vertical and horizontal directions. There were substantial variations between bowlers in both peak forces (vertical 6.7 ± 1.4 body weights; horizontal (braking) 4.5 ± 0.8 body weights) and times to peak force (vertical 0.03 ± 0.01 s; horizontal 0.03 ± 0.01 s). These differences were found to be linked to the orientation of the front leg at the instant of front foot contact. In particular, a larger plant angle and a heel strike technique were associated with lower peak forces and longer times to peak force during the front foot contact phase, which may help reduce the likelihood of lower back injuries.

Does maximising ball speed in cricket fast bowling necessitate higher ground reaction forces?

“…Four kinematic parameters that have previously been linked with ball speed (run-up speed, knee angle at ball release, upper trunk flexion (angle change from front foot contact until ball release) and shoulder angle at front foot contact; see Worthington et al, 2013a for further details), and three parameters that have been linked to peak ground reaction forces and time to peak force during front foot contact (plant angle at front foot contact, foot angle at front foot contact and knee flexion from front foot contact to ball release; Worthington et al, 2013b) were chosen for this further analysis.…”

“…Angles describing the front knee (straight = 180°, flexed < 180°), upper trunk (straight = 0°, flexed < 0°) and shoulder (anatomical position = 0°, greater than 180° corresponds to flexed behind the line of the trunk) corresponded to the anatomical flexion / extension angle of the joint. The foot angle at front foot contact was calculated as the angle between the global y-axis (horizontal line pointing down the wicket) and a line joining a projection of the ankle and MTP joint centres onto the global vertical yz plane (Worthington et al, 2013b). A positive foot angle corresponds to a 'heel strike' at front foot contact and a negative foot angle corresponds to a 'forefoot strike' at front foot contact.…”

“…A positive foot angle corresponds to a 'heel strike' at front foot contact and a negative foot angle corresponds to a 'forefoot strike' at front foot contact. The two-dimensional plant angle at front foot contact was calculated as the angle between the downwards vertical and a line joining a projection of the front hip and ankle joint centres onto the global vertical (yz) plane (Worthington et al, 2013b).…”

“…This relationship explained 74% of the variation in ball speed across the group of 20 bowlers (Worthington et al, 2013a). Lower peak forces and longer times to peak force during front foot contact in both horizontal and vertical directions have been associated with; a heel strike technique (where the heel is the first part of the foot to contact the ground), and a larger plant angle (angle between the downwards vertical and the hip to ankle line) (Worthington et al, 2013b). However, the link between ball speed and ground reaction forces is not clear, with few studies addressing this issue directly.…”

“…They suggested this may dissipate ground reaction forces during the early part of the front foot contact phase whilst maximising ball release speed (Bartlett et al, 1996). However, Worthington et al (2013b) observed no significant difference in either peak vertical or peak horizontal ground reaction force when bowlers were classified according to Portus's front knee classification system (Portus et al, 2004). Although there has been a substantial amount of research on fast bowling biomechanics, it remains unclear whether achieving fast ball release speeds requires bowlers to be exposed to potentially injurious high ground reaction forces.…”