Evidence map›Paper›PMID 40014606›Full record

Trial reportPloS one2025

The effects of plyometric training with speed and weight overloads on volleyball players' strength, power, and jumping performance.

Ahmad Reza Iranpour, Mohammad Hemmatinafar, Javad Nemati, Mohsen Salesi, Hamed Esmaeili, Babak Imanian

Abstract readRandomized Controlled Trial
In one paragraph

Trial report in PloS one, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers.

0numbers the graph read from it
0cells of the map it votes in
3citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

3 citing papers in PubMed.

  1. Effects of weighted vestsFrontiers in physiology · 2026
    Article
  2. Article
  3. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors.

Ahmad Reza IranpourDepartment of Sport Sciences, Faculty of Education and Psychology, Shiraz University, Shiraz, Iran.
Mohammad HemmatinafarDepartment of Sport Sciences, Faculty of Education and Psychology, Shiraz University, Shiraz, Iran.ORCID 0000-0001-7585-7592
Javad NematiDepartment of Sport Sciences, Faculty of Education and Psychology, Shiraz University, Shiraz, Iran.
Mohsen SalesiDepartment of Sport Sciences, Faculty of Education and Psychology, Shiraz University, Shiraz, Iran.
Hamed EsmaeiliDepartment of Sport Injuries and Corrective Exercise, Faculty of Sport Sciences, University of Isfahan, Isfahan, Iran.
Babak ImanianDepartment of Sport Sciences, Faculty of Education and Psychology, Shiraz University, Shiraz, Iran.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundThe principle of gradual overload is crucial in improving sports performance, yet the effects of combining speed and weight overloads in plyometric training remain understudied.

objectiveThis study investigated the effects of plyometric training with speed and weight overloads on isokinetic strength, explosive power, and agility in volleyball players.

methodForty male volleyball players were randomly assigned to four groups: plyometric training (PT), plyometric training with speed overload (PTS), plyometric training with weight overload (PTW), and plyometric training with both speed and weight overload (PTSW). Each group completed a four-week plyometric training regimen. Performance metrics, including Sarjent's jump height (SJH), Spike jump height (SPJH), Sheppard test (ShT), muscle voluntary isometric contraction (MVIC), rate of force development (RFD), absolute peak torque (PTQ), relative peak torque (RPT), and average power (AP) of knee extensors and flexors were measured before and after the intervention.

resultsSJH improved significantly in PTS (P = 0.012), PTW (P = 0.041), and PTSW (P = 0.001) compared to PT. SPJH showed substantial gains in PTS (P = 0.002), PTW (P = 0.001), and PTSW (P = 0.001) compared to PT. Average jump height and highest jump in ShT were also significantly higher in PTS, PTW, and PTSW (P < 0.05). Additionally, RFDext240°/s was enhanced considerably in PTS (P = 0.001) and PTSW (P = 0.001).

conclusionBased on the results, plyometric training with speed and weight overloads (PTSW) demonstrated superior enhancements in isokinetic strength, explosive power, and jumping performance. This combined approach is highly effective and significantly benefits male volleyball players, aiming to enhance their physical abilities.

Indexed as

Athletic PerformanceMuscle StrengthPlyometric ExerciseVolleyballAdultAthletesHumansIsometric ContractionMaleYoung Adult

Identifiers

PMID40014606
PMCPMC11867311

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.