Lengthened-Position Training: Does Stretch-Mediated Hypertrophy Increase Injury Risk?

A Popular Modern Training Approach

Training emphasising long muscle lengths — deep stretch positions under load, such as deficit lunges or Romanian deadlifts for the hamstrings — has become increasingly popular, driven by evidence that this kind of "stretch-mediated" loading can produce superior muscle hypertrophy compared with training confined to shorter muscle lengths.

Does More Growth Come With More Risk?

A controlled study directly comparing hamstring training at long versus short muscle lengths found that training at long muscle lengths produced significantly greater muscle hypertrophy, while measures of exercise-induced muscle damage were similar between the two conditions — suggesting the additional growth was not simply coming at the cost of excessive tissue damage (Maeo et al., 2021).

Evidence That Lengthened-Position Strength May Actually Protect Against Injury

More striking still, a landmark clinical trial of hamstring rehabilitation found that a programme specifically emphasising strength training at long muscle lengths produced a substantially lower hamstring re-injury rate than a more conventional protocol (Askling, Tengvar & Thorstensson, 2013) — turning the original injury-risk question on its head, with lengthened-position training now considered by many a protective strategy rather than a risk factor.