Effects of upper-body plyometric training on physical fitness in healthy youth and young adult participants: a systematic review with meta-analysis

Background Upper-body plyometric training (UBPT) is a commonly used training method, yet its efects on physical ftness are inconsistent and there is a lack of comprehensive reviews on the topic. Objective To examine the efects of UBPT on physical ftness in healthy youth and young adult participants com‑ pared to active, specifc-active, and passive controls. Methods This systematic review followed PRISMA 2020 guidelines and utilized the PICOS framework. PubMed, WOS, and SCOPUS were searched. Studies were assessed for eligibility using the PICOS framework. The efects of UBPT on upper-body physical ftness were assessed, including maximal strength, medicine ball throw performance, sportspecifc throwing performance, and upper limb muscle volume. The risk of bias was evaluated using the PEDro scale. Means and standard deviations were used to calculate efect sizes, and the I 2 statistic was used to assess heterogene‑ ity. Publication bias was assessed using the extended Egger’s test. Certainty of evidence was rated using the GRADE scale. Additional analyses included sensitivity analyses and adverse efects. Results Thirty-fve studies were included in the systematic review and 30 studies in meta-analyses, involving 1412 male and female participants from various sport-ftness backgrounds. Training duration ranged from 4 to 16 weeks. Compared to controls, UBPT improved maximal strength (small ES=0.39 95% CI=0.15–0.63, p=0.002, I 2=29.7%), medicine ball throw performance (moderate ES=0.64, 95% CI=0.43–0.85, p<0.001, I 2=46.3%), sport-specifc throw‑ ing performance (small ES=0.55, 95% CI=0.25–0.86, p<0.001, I 2=36.8%), and upper limbs muscle volume (moderate ES=0.64, 95% CI=0.20–1.08, p=0.005, I 2=0.0%). The GRADE analyses provided low or very low certainty for the rec‑ ommendation of UBPT for improving physical ftness in healthy participants. One study reported one participant with an injury due to UBPT. The other 34 included studies provided no report measure for adverse efects linked to UBPT. Conclusions UBPT interventions may enhance physical ftness in healthy youth and young adult individuals com‑ pared to control conditions. However, the certainty of evidence for these recommendations is low or very low. Further research is needed to establish the optimal dose of UBPT and to determine its efect on female participants and its transfer to other upper-body dominated sports.