Investigation of the Effects of Ski Ergometer-Based Training on Respiratory Functions and Isokinetic Muscle Strength in Cross-Country Skiers

<i>Background and Objectives</i>: Cross-country skiing requires high levels of upper-body strength and efficient respiratory function to sustain performance during sport-specific movements. This study aimed to examine the effects of an eight-week ski ergometer-based training program on upper-extremity isokinetic muscle strength and pulmonary function in competitive cross-country skiers. <i>Materials and Methods</i>: A total of 20 cross-country skiers voluntarily participated in the study (experimental group: <i>n</i> = 10, control group: <i>n</i> = 10). The research was conducted using a quasi-experimental controlled design. During the eight-week training period, the experimental group performed ski ergometer training three times per week at an intensity of 80-90% of maximal heart rate, with a target distance of 2.5 km per session, in addition to their regular training program. Measurements were obtained before and after the intervention. <i>Results:</i> Following the ski ergometer training period, significant increases were observed in FVC (F = 18.565, <i>p</i> < 0.001, ηp² = 0.508) and FEV₁ (F = 8.789, <i>p</i> = 0.008, ηp² = 0.328), which were associated with enhanced respiratory muscle endurance and ventilatory capacity. Regarding the isokinetic strength parameters, the DPPE60 variable showed significant main effects of time (F = 33.770, <i>p</i> < 0.001, ηp² = 0.652) and time × group interaction (F = 18.590, <i>p</i> < 0.001, ηp² = 0.508), indicating higher upper-extremity strength values across the measurement period. Additionally, strong positive correlations were found between dominant and nondominant limbs (r = 0.79-0.92; <i>p</i> < 0.05), indicating balanced bilateral strength development and high neuromuscular coordination. <i>Conclusions</i>: Ski ergometer-based training was associated with improvements in upper-extremity peak power (DPPE60) and ventilatory capacity (FVC) beyond general training-related adaptations. These findings suggest that SkiErg training may be a useful complementary method for enhancing selected performance-related physiological parameters in cross-country skiers.