The purpose of this study was to investigate the influence of a single static, ballistic, or proprioceptive neuromuscular facilitation (PNF) stretching exercise on the various muscle‐tendon parameters of the lower leg and to detect possible differences in the effects between the methods. Volunteers (n = 122) were randomly divided into static, ballistic, and PNF stretching groups and a control group. Before and after the 4 × 30 s stretching intervention, we determined the maximum dorsiflexion range of motion (RoM) with the corresponding fascicle length and pennation angle of the gastrocnemius medialis. Passive resistive torque (PRT) and maximum voluntary contraction (MVC) were measured with a dynamometer. Observation of muscle‐tendon junction (MTJ) displacement with ultrasound allowed us to determine the length changes in the tendon and muscle, respectively, and hence to calculate stiffness. Although RoM increased (static: +4.3%, ballistic: +4.5%, PNF: +3.5%), PRT (static: −11.4%, ballistic: −11.5%, PNF: −13,7%), muscle stiffness (static: −13.1%, ballistic: −20.3%, PNF: −20.2%), and muscle‐tendon stiffness (static: −11.3%, ballistic: −10.5%, PNF: −13.7%) decreased significantly in all the stretching groups. Only in the PNF stretching group, the pennation angle in the stretched position (−4.2%) and plantar flexor MVC (−4.6%) decreased significantly. Multivariate analysis showed no clinically relevant difference between the stretching groups. The increase in RoM and the decrease in PRT and muscle‐tendon stiffness could be explained by more compliant muscle tissue following a single static, ballistic, or PNF stretching exercise.

The purpose of this study was to determine the influence of upper and lower extremity movements on the volleyball spike jump (SJ) and how this movement may differ from the standing vertical jumps due to its asymmetry. The 3-D kinematics of body segments were measured in 16 experienced volleyball players with a VICON motion capture system. The jump heights (JH) of counter-movement (CM) and SJ were determined utilizing a force platform. A significant correlation was found between the JH during the SPJ and the maximal horizontal velocity of the center of mass (CoM) (r=0.71, p=0.002), the minimum height of the CoM (r=−0.68, p=0.004), the JH during CMJ (r=0.66, p=0.006) and SJ (r=0.74, p=0.001), the range of movement of right knee flexion-extension (r=0.76, p=0.001) and the angular velocity of left shoulder hyperextension (r=0.72, p=0.002). The asymmetry of the SJ revealed differences in angles, angular velocities of the right and left legs and arms, and a significant difference (p=0.001) between the distances of the left and right foot center to the CoM. Results of our study suggest the importance of optimal approach technique to reach a maximal JH in the volleyball SJ. The SJ movement is influenced by general jumping ability.

Background: A single foam-rolling exercise can acutely increase the range of motion (ROM) of a joint. However, to date the adaptational effects of foam-rolling training over several weeks on joint ROM are not well understood. Objective: The purpose of this meta-analysis was to investigate the effects of foam-rolling training interventions on joint ROM in healthy participants. Methods: Results were assessed from 11 studies (either controlled trials [CT] or randomized controlled trials [RCTs]) and 46 effect sizes by applying a random-effect meta-analysis. Moreover, by applying a mixed-effect model, we performed subgroup analyses, which included comparisons of the intervention duration (≤ 4 weeks vs > 4 weeks), comparisons between muscles tested (e.g., hamstrings vs quadriceps vs triceps surae), and study designs (RCT vs CT). Results: Our main analysis of 290 participants with a mean age of 23.9 (± 6.3 years) indicated a moderate effect of foam-rolling training on ROM increases in the experimental compared to the control group (ES = 0.823; Z = 3.237; 95% CI 0.325–1.322; p = 0.001; I² = 72.76). Subgroup analyses revealed no significant differences between study designs (p = 0.36). However, a significant difference was observed in the intervention duration in favor of interventions > 4 weeks compared to ≤ 4 weeks for ROM increases (p = 0.049). Moreover, a further subgroup analysis showed significant differences between the muscles tested (p = 0.047) in the eligible studies. Foam rolling increased joint ROM when applied to hamstrings and quadriceps, while no improvement in ankle dorsiflexion was observed when foam rolling was applied to triceps surae. Conclusion: Longer duration interventions (> 4 weeks) are needed to induce ROM gains while there is evidence that responses are muscle or joint specific. Future research should examine possible mechanisms underpinning ROM increases following different foam-rolling protocols, to allow for informed recommendations in healthy and clinical populations.