A Tissue That Genuinely Adapts, Slowly
Far from being an inert, rope-like structure, tendon is a living, adaptive tissue capable of meaningful structural change in response to heavy resistance training — it simply does so on a much longer timescale than muscle.
Hypertrophy That Is Surprisingly Localised
Imaging studies of the patellar tendon following a structured resistance training programme found that tendon hypertrophy occurred in a markedly region-specific pattern, with the greatest cross-sectional area increase occurring at the specific region bearing the highest mechanical strain during the training exercises used, rather than uniformly throughout the tendon's length (Kongsgaard et al., 2007).
Increased Stiffness, Not Just Increased Size
Alongside modest increases in cross-sectional area, heavy resistance training is consistently associated with increased tendon stiffness — a change in the tendon's mechanical properties that allows it to transmit muscular force more efficiently to the skeleton, and is considered at least as functionally significant as any change in the tendon's physical size.
References & Further Reading
- Kongsgaard M, Reitelseder S, Pedersen TG, et al. Region specific patellar tendon hypertrophy in humans following resistance training. Acta Physiol (Oxf). 2007;191(2):111-121.
- Bohm S, Mersmann F, Arampatzis A. Human tendon adaptation in response to mechanical loading: a systematic review and meta-analysis of exercise intervention studies on healthy adults. Sports Med Open. 2015;1(1):7.