Patellar tendon adaptation in relation to load-intensity and contraction type

Research output: Contribution to journalJournal articleResearchpeer-review

Peter Malliaras, Beenish Kamal, Alastair Nowell, Theo Farley, Hardev Dhamu, Victoria Simpson, Dylan Morrissey, Henning Langberg, Nicola Maffulli, Neil D Reeves

BACKGROUND: Loading leads to tendon adaptation but the influence of load-intensity and contraction type is unclear. Clinicians need to be aware of the type and intensity of loading required for tendon adaptation when prescribing exercise. The aim of this study was to investigate the influence of contraction type and load-intensity on patellar tendon mechanical properties. METHOD: Load intensity was determined using the 1 repetition maximum (RM) on a resistance exercise device at baseline and fortnightly intervals in four randomly allocated groups of healthy, young males: (1) control (no training); (2) concentric (80% of concentric-eccentric 1RM, 4×7-8); (3) standard load eccentric only (80% of concentric-eccentric 1RM, 4×12-15 repetitions) and (4) high load eccentric (80% of eccentric 1RM, 4×7-8 repetitions). Participants exercised three times a week for 12 weeks on a leg extension machine. Knee extension maximum torque, patellar tendon CSA and length were measured with dynamometry and ultrasound imaging. Patellar tendon force, stress and strain were calculated at 25%, 50%, 75% and 100% of maximum torque during isometric knee extension contractions, and stiffness and modulus at torque intervals of 50-75% and 75-100%. Within group and between group differences in CSA, force, elongation, stress, strain, stiffness and modulus were investigated. The same day reliability of patellar tendon measures was established with a subset of eight participants. RESULTS: Patellar tendon modulus increased in all exercise groups compared with the control group (p
Original languageEnglish
JournalJournal of Biomechanics
Volume46
Issue number11
Pages (from-to)1893–1899
DOIs
Publication statusPublished - 14 Jun 2013

ID: 46450496