Patrick Lunde

Objective: The aim of the study was to investigate the effect of eight weeks of in-season training with wearable resistance attached to the forearm on spike velocity in female volleyball players. Methods: A total of 13 senior female volleyball players belonging to the same team (age 23.5 ± 3.2 years, body mass 66.8 ± 6.9 kg, and height 174.7 ± 5.8 cm) participated and were divided into an experimental group (n = 7) or a control group (n = 6). Both groups participated in the same training sessions, but the experimental group trained with wearable resistance attached to the forearm, while the control group wore wearable resistance on the calf during the training sessions. Before and after an eight-week training period, spike velocity was tested. Results: The main findings were that spike velocity did not increase in either group, which was contrary to our hypothesis. In fact, neither the forearm-loaded experimental group nor the calf-loaded control group showed any performance improvement; instead, both groups demonstrated small, non-significant declines in spike velocity over the 8-week period (on average, about 2.1% in both groups). These outcomes occurred with high individual variability, with no significant difference between the groups (time × group: F(1, 11) = 0.008, p = 0.929). The between-group contrast was trivial, reinforcing that the forearm-loading intervention offered no clear benefit over normal training in practical terms. Conclusions: Taken at face value, this protocol does not support using wearable resistance during the competitive season to enhance spike velocity. It may be that off-season or individualized-load protocols could elicit more positive effects when overall training and fatigue levels are better controlled.

Background/Objectives: This study aimed to examine the effects of an eight-week wearable resistance (WR) training program on jump performance and jump kinematics in experienced senior female volleyball players. It was hypothesised that using WR would increase training load, thereby enhancing vertical jump performance and influencing kinematic movement patterns. Methods: Sixteen competitive female volleyball players (mean age: 23.5 ± 3.24 years; mean weight: 66.8 ± 6.9 kg; mean height: 174.7 ± 5.8 cm) participated in the study. Participants were randomly assigned to either a control group (n = 8) or an intervention group (n = 8) that trained with calf-mounted WR. The intervention group performed supervised resistance training sessions twice per week for eight weeks, totalling 16 sessions. Jump performance was assessed using an Infrared Optical Contact Grid (MuscleLab, Ergotest Innovation AS, Norway), and jump kinematics were measured with the Xsens Link motion capture system (Movella, The Netherlands). Results: The WR group demonstrated a statistically significant improvement in vertical jump height (p = 0.031), with no significant changes in kinematic variables. The control group, however, showed a significant increase in T8–pelvis flexion during the countermovement jump (CMJ) following the intervention period. Conclusions: Eight weeks of WR training can improve CMJ performance in-season among experienced female volleyball players without affecting movement kinematics. Future research should investigate optimal loading strategies and long-term adaptations. These findings suggest that integrating small wearable loads into regular volleyball practice can help athletes maintain and improve explosive performance without disrupting normal training routines.

Objectives: This study investigated the acute effects of pre-exercise cold-water immersion (CWI) on performance, muscle oxygen saturation, and mechanical muscle tension during calf raise training. Method: Twenty-four trained individuals (5 females, 19 males) were randomly assigned to either a CWI group (5 min at 10 ± 1 °C) or a non-CWI group (no intervention). Both groups performed three sets of standing calf raises to failure using a standardized protocol. Load lifted, repetitions, and rate of perceived exertion (RPE) were recorded. Muscle oxygenation (SmO₂, total hemoglobin) and mechanical muscle properties (frequency and stiffness) were measured before and after each set. Results: The CWI group showed a significantly greater increase in barbell load from set 1 to set 2 compared to the non-CWI group (from 94.5 ± 18.1 kg to 98.0 ± 18.7 kg, p < 0.01). Repetitions decreased and RPE increased across sets in both groups. The non-CWI group exhibited earlier increases in muscle stiffness and frequency, whereas these responses were delayed in the CWI group. Gastrocnemius SmO₂ increased during the protocol in the non-CWI group only. Total hemoglobin change was greater in the CWI group in set 1. Conclusions: These findings suggest that pre-exercise CWI may acutely enhance performance and delay neuromuscular fatigue without negatively affecting perceived effort.