Discussion
knee flexion
The results of the quantitative phase of our study revealed no differences between conventional neuromuscular training exercises and parkour-based actions when utilised within the warm-up protocols of pre-PHV basketball players. In relation to the Conventional warm-up group, our findings appear to contradict previous studies that have highlighted the efficacy of NMT-based warm-up programmes [In addition to the pedagogical delivery strategy, another possible explanation for our results may relate to the frequency of the warm-up exposure being limited to once per week. Typically, studies that have highlighted the efficacy of NMT-based warm-ups have prescribed two exposures per week (e.g., [Notwithstanding the results of our multivariate analyses, comparisons of within-group ES values for pre-post measures appeared to demonstrate that some specific adaptations were elicited in response to the stimuli of the respective warm-up programmes. Specifically, there were observed improvements in speed-related measures for the Conventional group, whereas both the Parkour and control groups showed a tendency to worsen in 10-m sprint performance, the largest effect of which was found in the control group. In the parkour-based speed-run test, however, while the largest within-group effect size was found for the Conventional group, the Parkour group also showed improvements in performance. In contrast, pre-post measures for the CMJ did not reveal any distinct changes, with very small effect sizes across all three groups. In the OHS knee flexion angles were found to improve with moderate effect sizes in the Conventional group and worsen in the Parkour and control groups. However, as might be expected, irrespective of group, at an individual level, each of the test measures revealed mixed results with some participants appearing to either show positive or negative changes greater than their pre-intervention CV. Thus, despite good levels of pre- and post-test reliability, the observed effect sizes were somewhat influenced by outliers, with some participants displaying substantially large differences between pre- and post-intervention measures, perhaps highlighting challenges associated with physical testing for empirical studies in preadolescent youths. In this regard it has previously been highlighted that in younger athletic populations, there may be increased variability in test performance due to limited physical development [Despite both warm-up interventions potentially preserving the young athletes’ physical fitness qualities, the medium to large between group ES, taken with the within-group ES difference across groups, appear to suggest that, for certain qualities, the Conventional warm-up was more effective than the Parkour-based warm-up. For example, the Conventional group’s exposure to acceleration speed is a likely explanation for their improvement in measure for 10-m sprint speed compared to the other groups. This may also account for the observed differences in OHS knee flexion achieved by the Conventional group compared to the Parkour and control groups. While the OHS was purposefully not included in the Conventional group’s warm-up, a bodyweight squat pattern (with arms held in front of the body) was included in each training session. Where the ability to perform a bodyweight squat to a depth of at least 90˚of knee flexion (or thighs parallel to the floor) is considered an indication of movement quality and neuromuscular control and movement skill [Somewhat contradicting to the apparent specific responses to the respective warm-up interventions’ content is observed in the Parkour group’s small ES value for the CMJ, despite being characterised by a greater volume of jumping and leaping activities compared to the Conventional group. However, as indicated by the observed changes across the groups against the pre-intervention CV values, there appeared to somewhat similar patterns of improvement in response to the different two warm-up interventions. A plausible explanation, therefore, is that the lack of prescription of exercise repetitions / foot contacts in the Parkour group in comparison to typical NMT-based warm-up programmes that prescribe progressively increasing volumes for each exercise (e.g., FIFA-11+). Indeed, the comparative results for the Conventional group, suggest that the low-structured prescription of exercises that characterised both interventions may have limited the development of jumping-related qualities.In summary, our quantitative results suggest that 15-minute NMT-based warm-up interventions offer some preservative benefits to the physical fitness qualities of pre-PHV athlete group. Moreover, as indicated in the results of the Parkour group’s warm-up intervention versus the control, there is potential merit to the incorporation of less conventional activities and exercises with the youth athletic development strategy.