Musculoskeletal stiffness during hopping and running does not change following downhill backwards walking
- Authors: Joseph, Corey , Bradshaw, Elizabeth , Kemp, Justin , Clark, Ross
- Date: 2014
- Type: Text , Journal article
- Relation: Sports Biomechanics Vol. 13, no. 3 (2014), p. 241-258
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- Description: Eccentric contractions that provide spring energy can also cause muscle damage. The aim of this study was to explore leg and vertical stiffness following muscle damage induced by an eccentric exercise protocol. Twenty active males completed 60 minutes of backward-walking on a treadmill at 0.67 m/s and a gradient of − 8.5° to induce muscle damage. Tests were performed immediately before; immediately post; and 24, 48, and 168 hours post eccentric exercise. Tests included running at 3.35 m/s and hopping at 2.2 Hz using single- and double-legged actions. Leg and vertical stiffness were measured from kinetic and kinematic data, and electromyography (EMG) of five muscles of the preferred limb were recorded during hopping. Increases in pain scores (over 37%) occurred post-exercise and 24 and 48 hours later (p < 0.001). A 7% decrease in maximal voluntary contraction occurred immediately post-exercise (p = 0.019). Changes in knee kinematics during single-legged hopping were observed 168 hours post (p < 0.05). No significant changes were observed in EMG, creatine kinase activity, leg, or vertical stiffness. Results indicate that knee mechanics may be altered to maintain consistent levels of leg and vertical stiffness when eccentric exercise-induced muscle damage is present in the lower legs. © 2014 Taylor & Francis.
Knee flexion strength is significantly reduced following competition in semi-professional Australian Rules football athletes : Implications for injury prevention programs
- Authors: Charlton, Paula , Raysmith, Benjamin , Wollin, Martin , Rice, Simon , Purdam, Craig , Clark, Ross , Drew, Michael
- Date: 2018
- Type: Text , Journal article
- Relation: Physical Therapy in Sport Vol. 31, no. (2018), p. 9-14
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- Description: Objectives: To evaluate strength and flexibility measures pre- and post- Australian Football (AF) competition to determine their potential utility as secondary prevention measures. Design: Cohort study. Setting: Semi-professional AF club. Participants: Ten male AF athletes (mean ± SD; age, 21.3 ± 2.2 years; height, 186.1 ± 6.3 cm; weight, 83.5 ± 8.6 kg). Main Outcome Measures: Maximal unilateral isometric knee flexion strength performed in 45 degrees of hip flexion and 30 degrees of knee flexion, flexibility measures of hip and knee extension and ankle dorsiflexion. All outcome measures were evaluated pre-match to determine baseline measurements and repeated acutely post-match and at 26, 50 and 74 h following. Comparisons were made between baseline measures and all other time points. Results: Knee flexion strength was significantly reduced at a group level acutely (−122.8N, 95%CI −156.2 to −89.4, p = 0.000) and at 26 h (−89.6N, 95%CI −122.9 to −56.2, p = 0.000) following competition. Hamstring flexibility was significantly reduced at all time periods following competition (all p < 0.05), however these values were not clinically meaningful. Conclusions: Knowledge that unilateral isometric knee flexion strength returns to pre-competition levels by 50 h following match-play in AF athletes is valuable for planning recovery time frames and may inform implementation of secondary prevention strategies. © 2018 Elsevier Ltd
Early changes in Achilles tendon behaviour in vivo following downhill backwards walking
- Authors: Joseph, Corey , Bradshaw, Elizabeth , Furness, Trentham , Kemp, Justin , Clark, Ross
- Date: 2016
- Type: Text , Journal article
- Relation: Journal of Sports Sciences Vol. 34, no. 13 (Jul 2016), p. 1215-1221
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- Description: Downhill backwards walking causes repeated, cyclical loading of the muscle-tendon unit. The effect this type of repeated loading has on the mechanical behaviour of the Achilles tendon is presently unknown. This study aimed to investigate the biomechanical response of the Achilles tendon aponeurosis complex following a downhill backwards walking protocol. Twenty active males (age: 22.3 +/- 3.0years; mass: 74.7 +/- 5.6kg; height: 1.8 +/- 0.7m) performed 60min of downhill (8.5 degrees), backwards walking on a treadmill at -0.67m center dot s(-1). Data were collected before, immediately post, and 24-, 48- and 168-h post-downhill backwards walking. Achilles tendon aponeurosis elongation, strain and stiffness were measured using ultrasonography. Muscle force decreased immediately post-downhill backward walking (P=0.019). There were increases in Achilles tendon aponeurosis stiffness at 24-h post-downhill backward walking (307 +/- 179.6N center dot mm(-1), P=0.004), and decreases in Achilles tendon aponeurosis strain during maximum voluntary contraction at 24 (3.8 +/- 1.7%, P=0.008) and 48h (3.9 +/- 1.8%, P=0.002) post. Repeated cyclical loading of downhill backwards walking affects the behaviour of the muscle-tendon unit, most likely by altering muscle compliance, and these changes result in tendon stiffness increases.
Exercise interventions for the prevention and treatment of groin pain and injury in athletes : A critical and systematic review
- Authors: Charlton, Paula , Drew, Michael , Mentiplay, Benjamin , Grimaldi, Alison , Clark, Ross
- Date: 2017
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 47, no. 10 (2017), p. 2011-2026
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- Description: Background: Groin injury is a common musculoskeletal complaint for athletes competing in a variety of sports. The extent to which exercise interventions incorporating external load are an appropriate option for the treatment and prevention of groin injury in athletes is not yet clear. Objectives: The aim of this review was to describe and evaluate exercise therapy interventions and outcomes for the treatment and prevention of groin injury with specific attention to application of external load. Data Sources: The databases Medline, PubMed, SPORTDiscus, Web of Science, and Cochrane were searched on 18 April 2016. Study Eligibility Criteria: This review was registered as PROSPERO CRD42016037752 and a systematic search was conducted with the following inclusion criteria: any study design evaluating exercise interventions for the prevention or treatment of groin pain in athletes. Data Analysis: Two independent authors screened search results, performed data extraction, assessed risk of bias using the modified Downs and Black appraisal tool and determined strength and level of evidence. Reporting standards for exercise interventions were assessed using the Consensus for Exercise Reporting Template (CERT). Results: A total of 1320 titles were identified with 14 studies satisfying the inclusion criteria, four (29%) of which demonstrated low risk of bias. Ten (71%) studies utilised external load as a component of the exercise intervention. Reporting standards for exercise intervention scores ranged from 0 to 63%. Conclusion: There is limited evidence from level 2 and 3 studies indicating exercise therapy may reduce the incidence and hazard risk of sustaining a groin injury in athletes. There is strong evidence from level 4 studies indicating exercise therapy is beneficial as a treatment for groin injury in athletes in terms of symptom remission, return to sport and recurrence outcomes. However, there are limited studies with low risk of bias, and exercise interventions for the treatment of groin injury are poorly described. © 2017, Springer International Publishing Switzerland.