Arm related bioelectrical impedance values are associated with handgrip strength in young tennis players

PURPOSE The aims of the study were to investigate differences in handgrip strength between right and left hand in young tennis players and whether such differences can be attributed to differences in localized (arm) bioelectrical impedance values, i.e. resistance (R), reactance (Xc) and phase angle (PA). METHODS A localized bioelectrical impedance analysis (BIA 101 sport edition, Akern – Italy) was performed on the right and the left arm in 34 young tennis players (male/female: n=23/11; age: 11.9±1.9 yr, height: 1.54±0.13 m; weight: 47.3±12.6 kg; left/right hander: n=7/27). Furthermore, hand grip strength (Fabrication Enterprises Ing. Irvington, NY) was tested on both sides. Differences between right and left hand were evaluated by student t-tests. Multiple linear regression analysis (backward method) was applied to investigate predictors (i.e., sex, age, weight, dominant side and R, Xc and PA of the right (dx) and left (sx) arm) determining the hand grip strength on both sides. RESULTS The hand grip strength was higher on the dominant side (right hander: right/left hand 21.3±7.4 vs 18.4±5.5 kg; left hander: 21.9±9.0 vs 24.6±9.0 kg, respectively, p<0.05). Furthermore, R was lower on the dominant side (right hander: right/left arm 252.5±31.0 vs 264.0±35.4 ohm; left hander: 261.8±32.8 vs 242.6±36.2, respectively, p<0.05), Xc was higher on the dominant side in right hander only (right/left arm 22.8±6.7 vs 21.3±2.2 ohm, p<0.05), and PA was higher on the dominant side in both, right and left hander (right hander: right/left arm 5.2±0.9 vs 4.7±0.6 ohm; left hander: 4.6±0.6 vs 5.3±0.8, respectively, p<0.05). Multiple linear regression analysis revealed that hand grip strength of the left side was determined by weight, R (sx), Xc (sx) and PA (sx) (R²=0.892). Hand grip strength of the right side was determined by age, weight, dominant side, R (dx), Xc (dx) and PA (dx, sx) (R²=0.893). CONCLUSION Present data show that differences in bioelectrical impedance values, which reflect water content (i.e., R) and cell integrity and function (i.e., Xc and PA), exists between the dominant and non-dominant side in young tennis players. Furthermore, these differences in impedance, beside others, were found to predict hand grip strength.