Comparative effects of suspension-based and dynamometer-based isometric training on neuromuscular performance in trained male athletes: a randomized comparative study

Objectives Isometric strength training is widely used to enhance athletic performance and support rehabilitation. However, few studies compare the effects of dynamometer-based and suspension-based isometric training on performance, and the effects of these methods remain unclear. This study compares the effects of dynamometer-based and suspension-based isometric training on muscle asymmetry, balance, estimated maximal strength, anaerobic power, and isokinetic strength in trained male athletes. Methods This study included 16 healthy male athletes aged 18 to 21 years (mean age: 18.81 ± 1.16 years; height: 178.06 ± 4.65 cm; body weight: 74.25 ± 4.32 kg; BMI: 23.43 ± 1.24 kg/m 2 ; body fat: 14.29 ± 1.55%). Participants were randomly assigned to either the TRX-based isometric training group (TRG, n=8) or the dynamometer-based isometric training group (DTG, n=8). Both groups performed isometric strength training based on the principle of progressive overload for eight weeks. The TRG group completed a predetermined series of four exercises three days per week. In contrast, the DTG group performed 6-second isometric contraction series in both flexion and extension positions for each leg three days per week. We assessed data normality using the Shapiro-Wilk test and calculated the mean and standard deviation. The relationship between pre-test and post-test measurements in the TRG and DTG groups was analyzed using a two-way repeated-measures analysis of variance (ANOVA; time × group); the level of statistical significance was set at p <.05. Results A significant main effect of time from the pretest to the posttest was found for the parameters of isokinetic peak torque, OSI, MLI, peak power, average power, and estimated 1RM (p <.05). In contrast, no significant main effect of time was observed for muscle asymmetry, API, and time to reach peak power (p>.05). Furthermore, it was stated that neither the group effect nor the time × group interaction showed a statistically significant effect on any of the performance parameters (p>.05). Conclusion In conclusion, while an eight-week TRX and dynamometer-based isometric training program resulted in significant changes in selected strength, balance, and anaerobic power parameters attributable to the main effect of time, no significant changes were observed in group effects or time × group interactions for any of the measured parameters.