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Plyometric training is frequently used to improve the jumping performance of volleyball players. The aim of the present study was to synthesize the results of different systematic reviews that investigated the effects of plyometric training on the jumping performance of volleyball players. Systematic research was performed in PubMed, Scopus, and Web of Science databases, looking for systematic reviews of randomized clinical trials. Methodological quality was independently assessed by two authors using AMSTAR. Four systematic reviews were included in the evidence synthesis, representing 983 volleyball players, 541 women and 314 men (128 were not declared). In summary, the studies lasted from 2 to 26 weeks of intervention, weekly frequency between 1-3, 1-6 sets, 1-25 repetitions and between 1-9 exercises per training session. AMSTAR indicated two studies with low quality of evidence, one moderate and one with high quality. The vertical jump was the main skill assessed in plyometric training interventions compared to the horizontal jump. According to the evidence, plyometric training had a positive effect on the vertical jump performance and on the maintenance of horizontal jumps of volleyball athletes. Further studies should look at mechanisms that lead to improvements in horizontal jump, and plyometric training programs should possibly include more horizontal jump exercises to optimize this skill. Keywords: strength and conditioning, stretch-shortening cycle, sport performance, sport science.

# Background Despite shoulder and elbow injuries being common in athletics, return to sport and reinjury rates are less than ideal. These outcomes may be driven by the absence of evidence-informed testing to determine an athlete's readiness for sport. # Purpose The purpose of this study was to explore the reported frequency of physical performance testing for return to sport readiness by physical therapists treating athletes with upper extremity injuries and to identify potential barriers that may limit use of these tests. A secondary aim was to compare practice patterns of clinicians with sports physical therapy specialty certification to clinicians without. # Study Design International, cross-sectional survey using purposive sampling. # Methods A survey instrument was created to assess the frequency of use of physical performance tests by physical therapists treating athletes with upper extremity injuries, as well as the barriers limiting the use of these tests. The 19-question online survey was distributed via email and Twitter among sports physical therapists. Independent t-tests and Chi Square analyses were conducted to determine differences in practice patterns between physical therapists with and without specialization and the frequency of potential barriers that may limit the use of these tests. # Results Four hundred ninety-eight participants met study eligibility and completed the survey. Fewer than half of participants reported using any physical performance test in making return to sport decisions for athletes with upper extremity injuries. The greatest barriers to the use of physical performance tests were a lack of equipment followed by lack of understanding of the literature, lack of time, and lack of supporting literature. Sports specialist clinicians were significantly more likely (p\