Table 2.
Means (standard deviations) for the two grips for forehand topspin and backspin strokes.
| Variables | Forehand Topspin | Forehand Backspin | ||
|---|---|---|---|---|
| Shakehand (n=18) | Penhold (n=9) | Shakehand (n=18) | Penhold (n=9) | |
| Ball forward (+) velocity (m/s) | 16.10 (1.13) | 15.89 (1.45) | 14.52 (1.10) | 14.37 (0.78) |
| Ball downward velocity (-) (m/s) | -1.80 (-0.26) | -1.72 (-0.16) | -1.41 (-0.27) | -1.40 (-0.27) |
| Peak racket resultant velocity (m/s) | 18.62 (1.51) | 18.15 (1.33) | 18.76 (1.52) | 18.37 (1.89) |
| Timing of peak racket resultant velocity (s) | 0.11 (0.01) | 0.14 (0.04) * | 0.11 (0.02) | 0.12 (0.04) |
| Initial trunk right rotation (-) angle (°) | -19.86 (11.76) | -11.34 (12.01) | -16.35 (12.41) | -8.37 (11.94) |
| Final trunk right rotation (-) angle (°) | -5.99 (7.15) | -2.33 (7.29) | -6.08 (8.13) | -2.77 (7.47) |
| Trunk left (+) rotation angular velocity (°/s) | 154.2 (169.0) | 145.0 (67.7) | 97.1 (193.5) | 74.1 (83.5) |
| Initial shoulder abduction (-) angle (°) | -22.51 (8.62) | -28.00 (6.88) | -21.85 (7.90) | -27.25 (8.66) |
| Final shoulder abduction (-) angle (°) | -43.72 (7.64) | -48.35 (8.36) | -41.16 (6.21) | -45.20 (9.05) |
| Shoulder adduction (+) / abduction (-) angular velocity (°/s) | -34.53 (161.52) | 42.77 (220.86) | -3.78 (166.88) | 13.63 (194.06) |
| Initial shoulder flexion (-) angle (°) | -15.40 (19.33) | -16.35 (18.39) | -14.44 (18.66) | -12.73 (20.52) |
| Final shoulder flexion (-) angle (°) | -57.07 (16.81) | -60.66 (17.72) | -60.61 (17.90) | -59.57 (19.60) |
| Shoulder flexion (-) angular velocity (°/s) | -802.5 (268.8) | -953.6 (281.8) | -775.4 (248.7) | -998.6 (332.0) |
| Initial shoulder external rotation (-) angle (°) | -42.62 (10.72) | -27.88 (19.81) * | -43.50 (10.41) | -33.80 (16.52) |
| Final shoulder internal (+) / external (-) rotation angle (°) | -9.88 (14.78) | 6.94 (18.63) * | -6.84 (13.43) | 5.49 (19.35) |
| Shoulder internal (+) rotation angular velocity (°/s) | 1096.6 (237.8) | 1082.1 (340.8) | 1099.0 (236.3) | 1077.1 (336.8) |
| Initial elbow flexion (-) angle (°) | -55.73 (15.11) | -56.11 (15.91) | -56.54 (16.60) | -55.67 (19.46) |
| Final elbow flexion (-) angle (°) | -59.09 (14.74) | -53.33 (15.09) | -59.89 (14.97) | -56.22 (18.18) |
| Elbow flexion (-) angular velocity (°/s) | -72.15 (172.66) | -176.18 (149.32) | -78.80 (204.59) | -191.12 (191.99) |
| Initial forearm pronation (+) angle (°) | 129.6 (18.0) | 137.0 (16.2) | 130.3 (20.1) | 133.0 (17.7) |
| Final forearm pronation (+) angle (°) | 132.4 (14.2) | 136.7 (16.7) | 133.1 (14.6) | 137.6 (16.6) |
| Forearm pronation (+) angular velocity (°/s) | 98.5 (180.7) | 213.6 (111.1) | 102.1 (210.3) | 207.3 (116.8) |
| Initial racket adduction (+) angle (°) | 6.59 (13.96) | 44.98 (11.13) # | 8.13 (14.38) | 45.66 (11.38) # |
| Final racket adduction (+) / abduction (-) angle (°) | 2.66 (12.73) | 34.70 (9.28) # | 2.35 (13.14) | 32.98 (10.20) # |
| Racket adduction (+) / abduction (-) angular velocity (°/s) | -175.6 (75.3) | -212.7 (121.5) | -191.7 (94.1) | -194.9 (108.6) |
| Initial racket extension (+) / flexion (-) angle (°) | 1.99 (19.38) | -48.28 (23.87) # | 2.35 (21.16) | -45.97 (25.84) # |
| Final racket extension (+) / flexion (-) angle (°) | 0.38 (14.17) | -33.28 (17.52) # | 0.02 (14.20) | -33.19 (15.43) # |
| Racket extension (+) / flexion (-) angular velocity (°/s) | -47.8 (102.1) | 196.1(99.6) # | -26.9 (121.1) | 189.1 (116.7) # |
| Initial racket external rotation (-) angle (°) | -28.65 (18.63) | -79.10 (15.14) # | -28.33 (19.76) | -79.17 (17.29) # |
| Final racket external rotation (-) angle (°) | -31.32 (16.16) | -72.13 (12.43) # | -31.25 (16.79) | -70.14 (12.62) # |
| Racket internal (+) rotation angular velocity (°/s) | 13.23 (87.14) | 106.88 (78.35) * | 16.49 (101.37) | 88.21 (90.30) |
Initial joint angles were extracted at the initiation of the forward stroke. Final joint angles and angular velocities were extracted at the time of the peak racket resultant velocity.
* p < 0.05,
# p < 0.001.