The different effects of intermittent and continuous stretching on the mechanical properties of the musculotendinous complex have been unclear. This study aimed to compare the effects of intermittent and continuous stretching for the same duration on the range of motion (ROM), passive resistive torque (PRT), and musculotendinous stiffness (MTS) of ankle plantar flexors. Eighteen healthy young men participated in the study. Intermittent (four sets × 30 s) and continuous stretching (one set × 120 s) were performed in random orders on two separate days. Both stretching protocols were conducted using a dynamometer with a constant torque applied. ROM and PRT were determined using a dynamometer, and MTS was calculated using the torque–angle relationship measured before and after stretching. Two-way repeated measures analysis of variance was performed for all parameters. Both intermittent and continuous stretching significantly increased ROM and decreased PRT and MTS (p < 0.05). Intermittent stretching led to greater changes in ROM and PRT than continuous stretching. However, the reduction in MTS did not differ between the two conditions. These results suggest that intermittent stretching is more effective in increasing ROM and changing the mechanical properties of the musculotendinous complex.

The purpose of this study was to determine how the application of static stretching to ankle plantar flexors affects postural control during maximum forward leaning. Twenty-six volunteer males (age 21.4 ± 1.2 years) were randomly assigned to stretching and control conditions. Participants conducted 5-min stretching on a stretch board for the stretching condition and were kept standing for 6-min for the control condition. Before and after intervention, the range of motion (ROM) at ankle dorsiflexion and the center of pressure (COP) excursion during maximal forward leaning were determined. Mean anteroposterior COP position, COP velocity and COP areas were calculated to compare the change in postural control. After stretching, ROM was significantly increased. During maximal forward leaning after stretching, both COP position and velocity showed significant increases compared to before stretching. Moreover, COP position and velocity in the stretching condition were significantly higher than in the control condition after stretching. No significant differences were found in COP area before and after stretching. Five-minute stretching increased not only ROM but also the anterior limit of stability while maintaining posture and led to faster COP shift than before stretching. These results indicate that static stretching would improve dynamic postural control as well.

Dynamic stretching (DS) uses a controlled movement through the range of motion (ROM) of the active joint(s) by contracting the agonist muscles without being held in an end position. In contrast, ballistic stretching (BS) typically uses uncontrolled movements of a higher velocity with bouncing actions. However, BS is often considered to be a form of DS. When considered together, DS and BS reportedly increase flexibility, evidenced by single- and multiple-joint ROM improvements and other measurements. However, a meta-analysis with subgroup analyses revealing the acute effects of DS and BS on flexibility in detail, independently of other stretching methods, has yet to be conducted. The purpose of this meta-analysis was to investigate the acute effects of DS and BS on flexibility in healthy participants. The PubMed, Web of Science, and Scopus databases were searched for eligible papers published before September 9, 2024; 17 papers were included in the meta-analysis. The main meta-analysis was performed with a random-effect model, and subgroup analyses were performed to examine the effects of age (young vs. middle-aged and older), sex (male vs. mixed sex), stretching methods (DS vs. BS), stretched muscles (hamstrings vs. plantar flexors vs. multiple muscles), and flexibility outcomes (single-joint ROM vs. straight-leg raise test vs. sit-and-reach test). A small increase in flexibility was found following DS and BS (considered together) (effect size = 0.372, Z = 3.936, 95% confidence interval = 0.187–0.557, p < 0.001, I2 = 27%). Subgroup analyses revealed no significant differences between age (p = 0.24), sex (p = 0.76), stretching method (p = 0.83), stretched muscle (p = 0.20), or flexibility outcome (p = 0.34) groups. Our results suggest that DS and BS effectively provide acute, small-magnitude improvements in flexibility that are not significantly affected by individual characteristics, stretching methods, stretched muscles, or flexibility outcomes.

Dynamic stretching (DS) is performed as a warm-up to improve the range of motion and athletic performance. However, the effect of different amounts of DS on muscle performance remains unclear. This study investigated the effects of DS repetitions with one or four sets of 30 s on musculotendinous extensibility and muscle strength. Fourteen healthy men (23.6 ± 1.5 years) underwent DS to ankle plantar flexors for one set (fifteen repetitions) or four sets after warm-up. The maximal ankle dorsiflexion angle, musculotendinous stiffness (MTS), passive torque, peak plantarflexion torque during maximal isometric contraction, and muscle temperature were measured before and after stretching. A significant effect of time was observed on the maximal ankle dorsiflexion angle, MTS, passive torque, and muscle temperature (p < 0.001). However, no interactions or effects between the conditions were observed. After DS, the maximal ankle dorsiflexion angle and muscle temperature significantly increased (p < 0.01), while the MTS and passive torque significantly decreased (p < 0.01). The maximal muscle strength showed no significant effects or interactions (p = 0.198−0.439). These results indicated that one and four sets of DS effectively increased musculotendinous extensibility. Thus, one set of DS may have similar effects as a warm-up before four sets of DS.