Effect of high time under tension strength training on different muscular actions in the performance of runners: A randomized controlled trial.

Runners are usually told to strength train with heavy weights and few repetitions, but this trial asked whether a different approach, using bodyweight exercises held under tension for longer periods, might also help. Thirty-four physically active young men were randomly assigned to four weeks of either dynamic strength training, isometric strength training, or no training, with each strength session matched for total time under muscular tension. The researchers looked at muscle strength, jump height, running economy, and a 3000-meter time trial.

Both training groups showed gains in leg strength and jump height compared with the control group, with the isometric group's strength gain and both groups' jump improvements reaching statistical significance. However, none of these neuromuscular improvements carried over into faster running or better running economy during the study period. The trial was small and short, so it tells us these training methods can build strength and power without necessarily translating into measurable running performance gains in just four weeks.

If you're a runner curious about strength training, this study looked at a less common approach: instead of lifting heavy weights for a few reps, participants did bodyweight exercises held for longer stretches of time, either moving through the exercise or holding a static position. Thirty-four young men were split into three groups, two doing this kind of training twice a week for four weeks, and one doing no strength training at all. The results showed that both types of training improved leg strength and jumping ability compared to the group that didn't train, with these differences reaching statistical significance for jump height in both groups and for strength in the isometric group.

That's a meaningful signal that these training styles can build power and strength in the legs. However, none of these gains showed up in actual running performance. The 3000-meter time trial and measures of running economy didn't improve any more than in the control group.

This was also a small, short study with only young men, so it can't tell us whether longer training periods, different exercises, or other populations would show different results, including for actual running speed or endurance.

This is a summary of research, not medical advice. Talk to your own healthcare provider about anything affecting your care.

This randomized controlled trial compared four weeks of dynamic versus isometric strength training, using bodyweight exercises equalized for time under tension per set (84 seconds), against a no-training control group in 34 physically active young men. Primary outcomes spanned neuromuscular measures (peak torque, countermovement jump, neuromuscular fatigue) and running-related measures (3000-meter time trial, internal running load, ground contact time, vertical oscillation), analyzed with two-way repeated measures ANOVA. Peak torque increased 13.3% in the dynamic group and 14.2% in the isometric group versus 2.5% in controls, but statistical significance was reached only for isometric training (p=0.034, d=1.12).

Countermovement jump height improved significantly in both dynamic (5.4%, p=0.003, d=1.54) and isometric (4.1%, p=0.030, d=1.13) groups relative to control. Despite these neuromuscular adaptations, no statistically significant changes emerged in running performance or running economy variables for either intervention group compared to control. The abstract does not report direct statistical comparisons between the dynamic and isometric groups themselves, so it cannot be concluded whether one contraction type outperformed the other beyond their respective comparisons with control.

The four-week duration and small sample size limit conclusions about whether longer exposure or different populations would yield performance transfer, and this dissociation between neuromuscular gains and running outcomes warrants cautious interpretation.