Related Experiment Video
Updated: May 10, 2026
04:37
A Passive Ankle Dorsiflexion Testing System for an In Vivo Model of Overuse-induced Tendinopathy
Published on: March 1, 2024
Patellar tendon adaptation in relation to load-intensity and contraction type.
Peter Malliaras1, Beenish Kamal, Alastair Nowell
1Centre for Sports and Exercise Medicine, Queen Mary, University of London, UK. p.malliaras@qmul.ac.uk
Journal of Biomechanics
|June 19, 2013
Summary
High load eccentric exercise significantly enhanced patellar tendon properties like modulus and force compared to other training types. This suggests specific loading protocols are crucial for tendon adaptation and strength gains.
Area of Science:
- Sports Science
- Biomechanics
- Tendon Physiology
Background:
- Tendon adaptation occurs with loading, but optimal load intensity and contraction type remain unclear.
- Understanding these factors is vital for clinicians prescribing exercise for tendon health.
- This study investigated how contraction type and load intensity affect patellar tendon mechanical properties.
Purpose of the Study:
- To determine the influence of different contraction types (concentric, eccentric) and load intensities on patellar tendon mechanical properties.
- To compare the effects of standard and high-load eccentric training versus concentric training and a control group.
Main Methods:
- Four groups of healthy young males underwent 12 weeks of training (control, concentric, standard eccentric, high-load eccentric) with load intensity based on 1RM.
- Measurements included knee extension torque, patellar tendon CSA and length, calculated force, stress, strain, stiffness, and modulus.
- Statistical analysis compared changes in tendon properties within and between groups.
Main Results:
- All exercise groups showed increased patellar tendon modulus compared to controls.
- The high-load eccentric group demonstrated significantly greater increases in maximum force, stiffness, and modulus at higher torque levels.
- All training groups improved 5 repetition maximum, with the high-load eccentric group showing the greatest gains.
Conclusions:
- Both load intensity and contraction type influence patellar tendon modulus.
- Muscle strength gains appear more sensitive to load intensity.
- High-load eccentric training was superior in enhancing tendon force, stiffness, and modulus, warranting further investigation into its clinical applications.
Related Concept Videos
01:22Isotonic and Isometric Muscle Contractions
Two primary types of muscle contractions are isotonic and isometric, each serving unique functions and involving distinct mechanisms. Both isotonic and isometric contractions are integral to the body's complex system of movement and stability. Isotonic exercises contribute significantly to functional strength and movement, while isometric contractions are crucial for maintaining posture and joint stability.
Isotonic contractions
Isotonic contractions occur when a muscle changes length while the...
Isotonic contractions
Isotonic contractions occur when a muscle changes length while the...
01:20Motor Unit Stimulation
When the neuron of a motor unit fires an action potential, it triggers a series of events, leading to a twitch contraction in the muscle fibers. The process of excitation-contraction coupling is crucial in relaying the action potential to the muscle fibers.
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...
01:26Tension Response at Adherens Junctions
The adherens junctions that anchor cells together are multi-protein complexes that dynamically adapt to mechanical stimuli such as tensile forces and shear stress. Mechanosensory proteins in these junctions can sense such mechanical stimuli and undergo a shift in their conformation, resulting in an altered function — a process called mechanotransduction.
α-Catenin as a Mechanosensory Protein
The α-catenin of adherens junctions is an allosteric protein with three VH (vinculin homology) domains...
α-Catenin as a Mechanosensory Protein
The α-catenin of adherens junctions is an allosteric protein with three VH (vinculin homology) domains...
01:26Cellular Adaptation II: Hypertrophy
Hypertrophy is the increase in the size of individual cells, resulting in the enlargement of a tissue or organ. Unlike hyperplasia, which involves an increase in cell number, hypertrophy is characterized by an increase in cell volume. This process often occurs in response to higher functional demand or hormonal stimulation, leading to the production of more structural proteins and organelles, thereby enhancing the cells' work capacity.There are two primary types of hypertrophy: physiological...
01:27Exercise and Muscle Performance
Exercise induces a range of adaptations in muscle tissue, depending on the type and duration of activity. Such physical training can be broadly categorized into two types: endurance exercises and resistance exercises.
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...