Modulation of Stretch-Shortening-Cycle Behavior With Eccentric Loading of Triceps Surae: A Possible Therapeutic Mechanism
MetadataShow full item record
Context: Eccentric exercises are increasingly being used to treat lower-limb musculoskeletal conditions such as Achilles tendinopathy. Despite widespread clinical application and documented efficacy, mechanisms underpinning clinical benefit remain unclear. Positive adaptations in motor performance are a potential mechanism. Objective: To investigate how an eccentric loading intervention influences measures of stretch-shortening-cycle (SSC) behavior during a hopping task. Design: Within-subjects repeated-measures observational study. Setting: University motion-analysis laboratory. Participants: Healthy adults. Interventions: A single intervention of 5 sets of 10 eccentric plantar-flexion contractions at 6 repetitions maximum using a commercial seated calf-raise machine. Main Outcome Measures: Lower-limb stiffness, sagittal-plane ankle kinematics, and temporal muscle activity of the agonist (soleus) and antagonist (tibialis anterior) muscles, measured during submaximal hopping on a custom-built sledge-jump system. Results: Eccentric loading altered ankle kinematics during submaximal hopping; peak angle shifted to a less dorsiflexed position by 2.9° and ankle angle precontact shifted by 4.4° (P < .001). Lower-limb stiffness increased from 5.9 to 6.8 N/m (P < .001), while surface EMG measures of soleus occurred 14–44% earlier (P < .001) after the loading intervention. Conclusions: These findings suggest that eccentric loading alters SSC behavior in a manner reflective of improved motor performance. Decreased ankle excursion, increased lower-limb stiffness, and alterations in motor control may represent a positive adaptive response to eccentric loading. These findings support the theory that mechanisms underpinning eccentric loading for tendinopathy may in part be due to improved “buffering” of the tendon by the neuromuscular system.
Showing items related by title, author, creator and subject.
Multidimensional impact of low-Dye taping on low-load hopping in individuals with and without plantar fasciitisVan Tonder, T.; Allison, Garry; Hopper, D.; Grisbrook, Tiffany (2018)Objectives: Evaluate the acute effect of low-Dye, placebo and no tape on motor behaviour in individuals with plantar fasciitis (PF). Design: Prospective, experimental. Setting: Motion analysis laboratory. Participants: ...
Wild, Catherine; Grealish, A.; Hopper, D. (2017)Â© by the National Athletic Trainers' Association, Inc. Context: Because of the increasing popularity of participation in Irish dance, the incidence of lower limb injuries is high among this competitive population. ...
Eccentric Fatigue Modulates Stretch-shortening Cycle Effectiveness – A Possible Role in Lower Limb Overuse InjuriesDebenham, J.; Travers, M.; Gibson, W.; Campbell, Amity; Allison, Garry (2016)The role of fatigue in injury development is an important consideration for clinicians. In particular, the role of eccentric fatigue in stretch-shortening cycle (SSC) activities may be linked to lower limb overuse conditions. ...