Adding load to jump training is not proven better than unloaded plyometrics
In short
A systematic review of six randomised controlled trials in 214 soccer players compared loaded plyometric-jump training (LPJT) — jumps performed with vests or dumbbells — against unloaded jump training. It could not conclude that LPJT is superior. LPJT showed favourable within-group changes in horizontal jump and some strength and power variables, but unloaded training produced comparable improvements in vertical jump, linear sprint, change of direction and agility, and soccer-specific outcomes. Five trials raised some concerns and one carried a high risk of bias; GRADE certainty ranged from low to very low. The verdict is a possible alternative, not a better method.
Strapping on a vest or holding dumbbells during jump training rests on the intuition that more load means more adaptation. This review tested that intuition and stopped at a plain conclusion: there is not yet evidence that it beats jumping unloaded.
What was compared?
Four databases were searched from inception to February 2026, with an update in March, for randomised controlled trials comparing loaded plyometric-jump training against unloaded plyometrics or passive control. Six trials in 214 soccer players qualified. Methodological quality was rated with PEDro, risk of bias with RoB 2, and certainty of evidence with GRADE.
What did the added load improve?
Within groups, LPJT showed favourable changes in horizontal jump performance and some strength and power variables. The catch is the comparison: vertical jump, linear sprint, change of direction and agility, and soccer-specific outcomes improved comparably after unloaded training too. "It improved" holds; "it improved more" does not.
Why can't the conclusion be stronger?
The evidence base is small. Six trials, 214 participants, with individual samples smaller still. Five raised some concerns on risk of bias and one was high risk overall, and methodological heterogeneity meant results had to be synthesised narratively rather than pooled. GRADE certainty came out low to very low across outcomes.
So should you drop the vest?
No need. The review's own phrasing is "a possible alternative rather than a demonstrably superior approach." Read practically: if loaded jumps are already in your training and you enjoy them, keeping them costs nothing — but there is no basis for expecting extra return from adding them. For anyone chasing a strength score the priority is clearer still: load on the big three moves the number, not load on the jump. That light worn loads touch explosiveness but not maximal strength was covered in eight weeks of 2%-bodyweight limb loading.
Frequently asked questions
Is loaded jump training more effective than bodyweight plyometrics?
Current evidence does not show that. A systematic review of six randomised trials in 214 soccer players could not conclude that loaded plyometric-jump training is superior to the unloaded version, and certainty of evidence was low to very low.
Did loaded plyometrics improve anything?
Within groups, it showed favourable changes in horizontal jump performance and some strength and power variables. But vertical jump, linear sprint, change of direction, agility and soccer-specific outcomes improved comparably with unloaded jump training.
Why was the certainty of evidence rated so low?
Only six trials with 214 participants qualified; five raised some concerns on risk of bias and one was high risk overall. Methodological heterogeneity also meant the results had to be synthesised narratively rather than pooled statistically.
Should you stop if you already do them?
There is no reason to. The review positions loaded plyometrics as a possible alternative to unloaded training, not as harmful. There is simply no current basis for expecting additional benefit from adopting them.
Source: PubMed