Abstract des Autors

A cinematographic analysis of the drive off the front foot (D) and the forward defensive stroke (FD) was undertaken to establish the kinematic and kinetic factors involved in playing these strokes against medium-fast bowling. Fourteen provincial cricket batsmen were filmed at 100 Hz while batting on a turf pitch with a specially instrumented bat. Results for the drive off the front foot revealed that the movement and stroke pattern were generally supportive of the coaching literature, with the forward defensive stroke forming the basis of the drive. Certain mechanical differences, although non-significant, were evident to facilitate the attacking nature of the front foot drive and included a higher backlift (FD = 0.65 m; D = 0.74 m), later commencement of the stride (FD = 0.64 s pre-impact; D = 0.58 s pre-impact) and downswing of the bat (FD = 0.38 s pre-impact; D = 0.36 s pre-impact), a shorter front foot stride (FD = 0.72 m; D = 0.68 m) with the front foot placement taking place later (FD = 0.14 s pre-impact; D = 0.06 s pre-impact), and the back foot dragging further forward at impact (FD = 0.05 m; D = 0.10 m). The front upper limb moved as a multi-segmental series of levers, which resulted in the drive showing significantly greater (P<0.05) peak bat horizontal velocity at 0.02 s pre-impact (FD = 3.53+/-3.44 m/s; D = 11.8+/-4.61 m/s) and 0.02 s post-impact (FD = 2.73+/-2.88 m/s; D = 11.3+/-4.21 m/s). The drive showed a significantly greater (P<0.05) bat-ball closing horizontal velocity (FD = 24.2+/-4.65 m/s; D = 32.3+/-5.06 m/s) and post-impact ball horizontal velocity (FD = 6.85+/-5.12 m/s; D = 19.5+/-2.13 m/s) than for the forward defensive stroke. The point of bat-ball contact showed non-significant differences, but occurred further behind the front ankle (FD = 0.09+/-0.17 m; D = 0.20+/-0.13 m), with the bat more vertical at impact (FD = 62.6+/-6.53ø; D = 77.8+/-7.05ø). Significant differences (P<0.01) occurred between the grip forces of the top and bottom hands for the two strokes, with the principal kinetic finding that the top hand plays the dominant role during the execution of the drive with the bottom hand reinforcing it at impact. Similar grip force patterns for the two strokes occurred during the initial part of the stroke, with the drive recording significantly greater (P<0.05) forces at 0.02 s pre-impact (top hand: FD = 129+/-41.6 N; D = 199+/-40.9 N; bottom hand: FD = 52.2+/-16.9 N; D = 91.8+/-41.1 N), at impact (top hand: FD = 124+/-29.3 N; D = 158+/-56.2 N; bottom hand: FD = 67.1+/-21.5 N; D = 86.2+/-58.2 N) and 0.02 s post-impact (top hand: FD = 111+/-22.2 N; D = 126+/-28.5 N; bottom hand: FD = 65.5+/-26.9 N; D = 82.4+/-28.6 N). Verf.-Referat