Research article - (2026)25, 838 - 849
DOI:
https://doi.org/10.52082/jssm.2026.838
Effects of 10% Versus 30% Velocity Loss Thresholds on Strength and Explosive Performance in Trained Female Collegiate Athletes: A Randomized Parallel-Group Trial
Xuehaiyue Lv1, Jingyuan Yang1, LinTao Suo1, Longkang Guo1, Mushuai Hao1, Haonan Qi1, Wei Han1,
1School of Graduate Education, Shandong Sport University, Jinan, China
2School of Competitive Sports, Shandong Sport University, Rizhao,China
3School of Physical Education, Hebei Normal University, Shijiazhuang, China

Wei Han
✉ School of Competitive Sports, Shandong Sport University, Rizhao, China
Email: sdtyhw@163.com
Received: 01-08-2026 -- Accepted: 01-09-2026
Published (online): 01-12-2026
Narrated in English

ABSTRACT

This study compared the effects of 10% and 30% velocity-loss thresholds during Smith-machine squat training on maximal strength, jumping, and sprint performance in trained female collegiate athletes. Twenty-eight athletes were randomly assigned to a 10% velocity-loss group (VL10) or a 30% velocity-loss group (VL30).Both groups completed 8 weeks of supervised squat training twice weekly, performing four sets at 70% of one-repetition maximum, with each set terminated when the assigned threshold was reached. Smith-machine squat one-repetition maximum (1RM), squat jump (SJ), countermovement jump (CMJ), standing long jump (SLJ), and 30-m sprint (T30) performance were assessed before and after the intervention. Group × time effects were examined using mixed-design analyses of variance. Mean propulsive velocity was higher in VL10, whereas VL30 completed substantially more repetitions per set and per session (all p < 0.001). All performance outcomes improved over time (all p < 0.001). VL30 produced a greater increase in squat 1RM than VL10 (12.5% vs. 9.2%; interaction p < 0.001, ηp2 = 0.450). VL10 produced greater improvements in SLJ (interaction p = 0.031, ηp2 = 0.166) and T30 time (interaction p = 0.006, ηp2 = 0.254). Group × time interactions were not significant for SJ (p = 0.127) or CMJ (p = 0.058). Both thresholds improved strength and lower-body performance, but the adaptation pattern differed by outcome. Under the present protocol, VL30 favored 1RM squat strength, whereas VL10 favored SLJ and T30 performance.

Key words: Set termination, mean propulsive velocity, repetition volume, muscle fatigue, squat jump, sprinting

Key Points
  • Eight weeks of Smith-machine squat training with either 10% or 30% velocity-loss (VL) thresholds produced significant improvements in squat strength, jumping and sprint performance among resistance-trained female collegiate athletes, but the two protocols triggered task-specific adaptive differences.
  • The 30% VL group achieved greater gains in maximal squat strength, whereas the 10% VL group showed greater improvements in SLJ and T30 performance; changes in vertical jump performance did not differ significantly between the two groups.
  • Practitioners should choose VL thresholds according to periodized training targets: 30% VL is recommended for maximal lower-body strength development, whereas 10% VL is more suitable for optimizing horizontal explosive power and sprint performance in female athletes.








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