No sign of weakness: a systematic review and meta-analysis of hip and calf muscle strength after anterior cruciate ligament injury.

OBJECTIVE: We aimed to determine hip and lower-leg muscle strength in people after ACL injury compared with an uninjured control group (between people) and the uninjured contralateral limb (between limbs). DESIGN: Systematic review with meta-analysis. DATA SOURCES: MEDLINE, EMBASE, CINAHL, Scopus, Cochrane CENTRAL and SportDiscus to 28 February 2023. ELIGIBILITY CRITERIA: Primary ACL injury with mean age 18-40 years at time of injury. Studies had to measure hip and/or lower-leg muscle strength quantitatively (eg, dynamometer) and report muscle strength for the ACL-injured limb compared with: (i) an uninjured control group and/or (ii) the uninjured contralateral limb. Risk of bias was assessed according to Cochrane Collaboration domains. RESULTS: Twenty-eight studies were included (n=23 measured strength ≤12 months post-ACL reconstruction). Most examined hip abduction (16 studies), hip extension (12 studies) and hip external rotation (7 studies) strength. We found no meaningful difference in muscle strength between people or between limbs for hip abduction, extension, internal rotation, flexion or ankle plantarflexion, dorsiflexion (estimates ranged from -9% to +9% of comparator). The only non-zero differences identified were in hip adduction (24% stronger on ACL limb (95% CI 8% to 42%)) and hip external rotation strength (12% deficit on ACL limb (95% CI 6% to 18%)) compared with uninjured controls at follow-ups >12 months, however both results stemmed from only two studies. Certainty of evidence was very low for all outcomes and comparisons, and drawn primarily from the first year post-ACL reconstruction. CONCLUSION: Our results do not show widespread or substantial muscle weakness of the hip and lower-leg muscles after ACL injury, contrasting deficits of 10%-20% commonly reported for knee extensors and flexors. As it is unclear if deficits in hip and lower-leg muscle strength resolve with appropriate rehabilitation or no postinjury or postoperative weakness occurs, individualised assessment should guide training of hip and lower-leg strength following ACL injury. PROSPERO REGISTRATION NUMBER: CRD42020216793.

TENDINopathy Severity assessment-Achilles (TENDINS-A): evaluation of reliability and validity in accordance with COSMIN recommendations.

OBJECTIVE: To evaluate the construct validity (structural validity and hypothesis testing), reliability (test-retest reliability, measurement error and internal consistency) and minimal important change (MIC) of the 13-item TENDINopathy Severity assessment-Achilles (TENDINS-A). METHODS: Participants with Achilles pain completed an online survey including: demographics, TENDINS-A, Foot and Ankle Outcome Score (FAOS) and Victorian Institute of Sport Assessment-Achilles (VISA-A). Exploratory factor analysis (EFA) assessed dimensionality. Confirmatory factor analysis (CFA) assessed structural validity (root mean square error of approximation (RMSEA); Comparative Fit Index (CFI); Tucker-Lewis Index (TLI); standardised root measure square (SRMS)). Correlations between TENDINS-A and the FAOS or VISA-A assessed hypothesis testing. Intraclass correlation (ICC) assessed test-retest reliability. Cronbach's alpha assessed internal consistency. SE of the measurement (SEM) assessed measurement error. A distribution-based approach assessed MIC. RESULTS: 79 participants (51% female) with a mean (SD) age=42.6 (13.0) years, height=175.0 (11.7) cm and body mass=82.0 (19.1) kg were included. EFA identified three meaningful factors, proposed as pain, symptoms and function. The best model identified using CFA for TENDINS-A had structural validity (RMSEA=0.101, CFI=0.959, TLI=0.947, SRMS=0.068), which included three factors (pain, symptoms and function), but excluded three items from the original TENDINS-A. TENDINS-A exhibited moderate positive correlation with FAOS (r=0.598, p<0.001) and a moderate negative correlation with VISA-A (r=-0.639, p<0.001). Reliability of the TENDINS-A was excellent (ICC=0.930; Cronbach's α=0.808; SEM=6.54 units), with an MIC of 12 units. CONCLUSIONS: Our evaluation of the revised 10-item TENDINS-A determined it has construct validity and excellent reliability, compared with the VISA-A and FAOS which lack content and construct validity. The TENDINS-A is recommended as the preferred patient-reported outcome measure to assess disability in people with Achilles tendinopathy.

Sport and exercise medicine/physiotherapy publishing has a gender/sex equity problem: we need action now!

OBJECTIVES: We aimed to determine (1) the proportion of women authors overall, in first (lead) and last (senior) author positions, (2) the proportion of women research participants and (3) the association between women in first and/or last author positions and the proportion of women research participants in original research articles and editorials/opinion pieces in four sport and exercise medicine/physiotherapy journals. METHODS: The journals evaluated were the British Journal of Sports Medicine, Journal of Orthopaedic and Sports Physical Therapy, Physical Therapy in Sport and International Journal of Sports Physical Therapy.We reviewed all original research articles and editorials/opinion pieces published in 2008, 2009, 2018 and 2019. For each, we aimed to determine the gender/sex of all authors (through gender pronouns, Google Scholar, ResearchGate, institutional profiles, personal websites, photographs and/or social media), and the gender/sex of study participants reported as 'female' or 'male' or 'women' or 'men' or 'girls' or 'boys'. RESULTS: We included 952 original studies and 219 editorials/opinion pieces. There were 5146 authors of original studies and 706 authors of editorials/opinion pieces. Compared with 2008/2009, the proportion of women as first and last authors was 3.6% (33.0% compared with 29.4%) and 4.8% (33.2% compared with 27.4%) higher respectively in 2018/2019. On average, the proportion of women participants in original studies remained largely unchanged over the 10-year period, only 10% of all participants were women in studies. CONCLUSION: Women are strikingly under-represented in first and last author positions, as are women participants in sports and exercise medicine/physiotherapy journals.

Implicit Motor Imagery of the Foot and Hand in People with Achilles Tendinopathy: A Left Right Judgement Study.

OBJECTIVE: To determine if impairment in motor imagery processes is present in Achilles tendinopathy (AT), as demonstrated by a reduced ability to quickly and accurately identify the laterality (left-right judgement) of a pictured limb. Additionally, this study aimed to use a novel data pooling approach to combine data collected at 3 different sites via meta-analytical techniques that allow exploration of heterogeneity. DESIGN: Multi-site case-control study. METHODS: Three independent studies with similar protocols were conducted by separate research groups. Each study-site evaluated left/right judgement performance for images of feet and hands using Recognise© software and compared performance between people with AT and healthy controls. Results from each study-site were independently collated, then combined in a meta-analysis. RESULTS: In total, 126 participants (40 unilateral, 22 bilateral AT cases, 61 controls) were included. There were no differences between AT cases and controls for hand image accuracy and reaction time. Contrary to the hypothesis, there were no differences in performance between those with AT and controls for foot image reaction time, however there were conflicting findings for foot accuracy, based on four separate analyses. There were no differences between the affected and unaffected sides in people with unilateral AT. CONCLUSIONS: Impairments in motor imagery performance for hands were not found in this study, and we found inconsistent results for foot accuracy. This contrasts to studies in persistent pain of limbs, face and knee osteoarthritis, and suggests that differences in pathoetiology or patient demographics may uniquely influence proprioceptive representation.

Immediate Effects of two Isometric Calf Muscle Exercises on Mid-portion Achilles Tendon Pain.

The objectives of this randomized, cross-over pilot study were to determine whether isometric plantarflexion exercises resulted in an immediate change in Achilles tendon pain during a loading task, and whether this differed in knee extension or flexion. Eleven participants with mid-portion Achilles tendinopathy were recruited from NHS community physiotherapy services and local running clubs. Participants were then randomized to complete an isometric calf muscle exercise with the knee fully extended or flexed to 80°. Participants switched to the alternate exercise after a minimum seven-day period. Achilles tendon pain during a specific, functional load test was measured on a 11-point numeric pain rating scale (NPRS) pre- and post-intervention. There was a small, immediate, mean reduction in pain following isometric plantar flexion performed in both knee extension (1.6, 95%CI 0.83 to 2.45, p=0.001) and knee flexion (1.3, 95%CI 0.31 to 2.19, p=0.015). There were no significant differences between the two positions. A non-significant, potentially clinically relevant finding was a 20% larger reduction in symptoms in knee extension versus flexion (p=0.110). In conclusion, isometric plantarflexion holds gave an approximately 50% immediate reduction in Achilles tendon pain with a functional load test. There were no significant differences between the two positions and both were well tolerated.

Jump-landing mechanics in patellar tendinopathy in elite youth basketballers.

Patellar tendinopathy (PT) is a leading cause of morbidity in jump-landing athletes. Landing mechanics are identified as a factor associated with PT and/or patellar tendon abnormality. This study aimed to identify key jump-landing variables associated with PT. Thirty-six junior elite basketball players (men n = 18, women n = 18) were recruited from a Basketball Australia development camp. Three-dimensional (3D) kinematic and ground reaction force (GRF) data during a stop-jump task were collected as well as ultrasound scans of the patellar tendons and recall history of training load data. Mixed-model factorial analyses of variance were used to determine any significant between-group differences. Of the 23 participants included for statistical analyses, 11 had normal bilateral patellar tendons (controls) and eight reported PT (currently symptomatic); however, the four participants categorized as asymptomatic with patellar tendon abnormality on diagnostic imaging were excluded from statistical analyses due to their small sample size. Athletes with PT displayed a similar knee flexion angle at initial foot-ground contact (IC) and hip extension strategy during a stop-jump horizontal landing. Despite a similar kinematic technique, athletes with PT utilized a strategy of a longer stance duration phase from IC to peak force. This strategy did not lead to those athletes with PT decreasing their peak vertical GRF nor patellar tendon force during landing but enabled these athletes to land with a lower rate of loading (control 59.2 ± 39.3 vs. PT 29.4 ± 33.7 BW.s-1). Athletes with PT still reported significantly reduced training volume (control 4.9 ± 1.8 vs PT 1.8 ± 1.1 sessions/wk; total training time/wk control 2.4 ± 1.0 vs PT 1.4 ± 1.1 h/wk).

ICON PART-T 2019-International Scientific Tendinopathy Symposium Consensus: recommended standards for reporting participant characteristics in tendinopathy research (PART-T).

We aimed to establish consensus for reporting recommendations relating to participant characteristics in tendon research. A scoping literature review of tendinopathy studies (Achilles, patellar, hamstring, gluteal and elbow) was followed by an online survey and face-to-face consensus meeting with expert healthcare professionals (HCPs) at the International Scientific Tendon Symposium, Groningen 2018. We reviewed 263 papers to form statements for consensus and invited 30 HCPs from different disciplines and geographical locations; 28 completed the survey and 15 attended the meeting. There was consensus that the following data should be reported for cases and controls: sex, age, standing height, body mass, history of tendinopathy, whether imaging was used to confirm pathology, loading tests, pain location, symptom duration and severity, level of disability, comorbidities, physical activity level, recruitment source and strategies, and medication use history. Standardised reporting of participant characteristics aims to benefit patients and clinicians by guiding researchers in the conduct of their studies. We provide free resources to facilitate researchers adopting our recommendations.

ICON 2019-International Scientific Tendinopathy Symposium Consensus: There are nine core health-related domains for tendinopathy (CORE DOMAINS): Delphi study of healthcare professionals and patients.

BACKGROUND: The absence of any agreed-upon tendon health-related domains hampers advances in clinical tendinopathy research. This void means that researchers report a very wide range of outcome measures inconsistently. As a result, substantial synthesis/meta-analysis of tendon research findings is almost futile despite researchers publishing busily. We aimed to determine options for, and then define, core health-related domains for tendinopathy. METHODS: We conducted a Delphi study of healthcare professionals (HCP) and patients in a three-stage process. In stage 1, we extracted candidate domains from clinical trial reports and developed an online survey. Survey items took the form: 'The 'candidate domain' is important enough to be included as a core health-related domain of tendinopathy'; response options were: agree, disagree, or unsure. In stage 2, we administered the online survey and reported the findings. Stage 3 consisted of discussions of the findings of the survey at the ICON (International Scientific Tendinopathy Symposium Consensus) meeting. We set 70% participant agreement as the level required for a domain to be considered 'core'; similarly, 70% agreement was required for a domain to be relegated to 'not core' (see Results next). RESULTS: Twenty-eight HCP (92% of whom had >10 years of tendinopathy experience, 71% consulted >10 cases per month) and 32 patients completed the online survey. Fifteen HCP and two patients attended the consensus meeting. Of an original set of 24 candidate domains, the ICON group deemed nine domains to be core. These were: (1) patient rating of condition, (2) participation in life activities (day to day, work, sport), (3) pain on activity/loading, (4) function, (5) psychological factors, (6) physical function capacity, (7) disability, (8) quality of life and (9) pain over a specified time. Two of these (2, 6) were an amalgamation of five candidate domains. We agreed that seven other candidate domains were not core domains: range of motion, pain on clinician applied test, clinical examination, palpation, drop out, sensory modality pain and pain without other specification. We were undecided on the other five candidate domains of physical activity, structure, medication use, adverse effects and economic impact. CONCLUSION: Nine core domains for tendon research should guide reporting of outcomes in clinical trials. Further research should determine the best outcome measures for each specific tendinopathy (ie, core outcome sets).

Reduced Levels of Aligned Fibrillar Structure Are Not Associated With Achilles and Patellar Tendon Symptoms.

OBJECTIVE: To investigate whether the mean cross-sectional area (mCSA) of aligned fibrillar structure (AFS) was associated with the presence and severity of symptoms. DESIGN: Prospective cohort study. PARTICIPANTS: One hundred seventy-five elite male Australian football players completed monthly Oslo Sports Trauma Research Center overuse injury questionnaires for both the Achilles and patellar tendon over the season to ascertain the presence and severity of symptoms. At the start of the preseason, participants underwent ultrasound tissue characterization (UTC) imaging of the Achilles and patellar tendon. MAIN OUTCOME MEASURES: Images were classified as normal or abnormal based on gray-scale ultrasound. Based on UTC quantification, the mCSA of AFS was compared between those with and without current symptoms. RESULTS: No difference in the mCSA of AFS was observed between those with or without tendon symptoms (P < 0.05). Similar to previous findings, 80% to 92% of abnormal tendons had similar amounts of mCSA of AFS compared with normal tendon. If reduced mCSA of AFS was present, it was not associated with the presence or severity of symptoms. CONCLUSIONS: The prevalence, development, or severity of symptoms was not associated with decreased levels of AFS in the Achilles or patellar tendon. This suggests that a lack of structural integrity is not linked to symptoms and questions the rationale behind regenerative medicine. Most tendons are able to compensate for areas of disorganization and maintain tissue homeostasis.

Diagnostic accuracy of imaging modalities in the detection of clinically diagnosed de Quervain's syndrome: a systematic review.

OBJECTIVES: To collate and synthesise the literature to provide estimates of the diagnostic accuracy of imaging modalities, and summarise the reported imaging findings associated with de Quervain's syndrome. MATERIALS AND METHODS: A systematic search was performed in seven databases (MEDLINE, EMBASE, CINAHL, Cochrane Library, PROSPERO, Web of Science, and ProQuest Dissertations & Theses Global). Two reviewers independently performed screening, data extraction and quality assessment using a modified Quality Assessment of Diagnostic Accuracy Studies-2. Measures of diagnostic accuracy were summarised for different modalities and imaging findings. RESULTS: Twenty-two studies were included, reporting ultrasound, magnetic resonance imaging, X-ray and scintigraphy findings. Reported imaging findings included sheath effusion, retinaculum thickening, subcutaneous oedema, tenosynovitis, hypervascularity, increased tendon size, bony erosion, apposition, calcific lesions and increased uptake on scintigraphy. The most commonly reported imaging findings related to the tendon sheath, with a sensitivity ranging from 0.45 to 1.00 for thickening, and 0.29 to 1.00 for effusions. The risk of bias of studies is largely unclear owing to a lack of reported detail. CONCLUSIONS: The accuracy of imaging in the diagnosis of de Quervain's syndrome is unable to be determined because of the quality of the studies included. Ultrasound is the most frequently studied imaging modality and may be the modality of choice in clinical practice. Further research involving both symptomatic and asymptomatic participants and clear definitions of abnormal findings are required to better evaluate the effectiveness of imaging in identifying de Quervain's syndrome.

Efficacy of heavy eccentric calf training for treating mid-portion Achilles tendinopathy: a systematic review and meta-analysis.

OBJECTIVE: To assess the effectiveness of heavy eccentric calf training (HECT) in comparison with natural history, traditional physiotherapy, sham interventions or other exercise interventions for improvements in pain and function in mid-portion Achilles tendinopathy. DESIGN: A systematic review and meta-analysis were conducted as per the PRISMA guidelines. DATA SOURCES: PUBMED, CINAHL (Ovid) and CINAHL (EBSCO) were searched from inception until 24 September 2018. ELIGIBILITY CRITERIA: Randomised controlled trials comparing HECT to natural history, sham exercise, traditional physiotherapy and other exercise interventions were included. Primary outcome assessing pain and function was the Victorian Institute of Sports Assessment-Achilles. RESULTS: Seven studies met the inclusion criteria. This review suggests HECT may be superior to both natural history, mean difference (MD) (95% CI) of 20.6 (11.7 to 29.5, one study) and traditional physiotherapy, MD (95% CI) of 17.70 (3.75 to 31.66, two studies). Following removal of one study, at high risk of bias, due to pre-planned sensitivity analysis, this review suggests HECT may be inferior to other exercise interventions, MD (95% CI) of -5.65 (-10.51 to -0.79, three studies). However, this difference is unlikely to be clinically significant. CONCLUSION: Current evidence suggests that HECT may be superior to natural history and traditional physiotherapy while HECT may be inferior to other exercise interventions. However, due to methodological limitations, small sample size and a lack of data we are unable to be confident in the results of the estimate of the effect, as the true effect is likely to be substantially different. SYSTEMATIC REVIEW REGISTRY: PROSPERO registration number: CRD4201804493 PROTOCOL REFERENCE: This protocol has been published open access: Murphy M, Travers MJ, Gibson, W. Is heavy eccentric calf training superior to natural history, sham rehabilitation, traditional physiotherapy and other exercise interventions for pain and function in mid-portion Achilles tendinopathy? Systematic Reviews 2018; 7: 58.

Isometric Exercise to Reduce Pain in Patellar Tendinopathy In-Season: Is It Effective "on the Road"?

OBJECTIVE: To investigate the effectiveness of an isometric squat exercise using a portable belt, on patellar tendon pain and function, in athletes during their competitive season. DESIGN: Case series with no requirements to change any aspect of games or training. The object of this pragmatic study was to investigate this intervention in addition to "usual management." A control or sham intervention was considered unacceptable to teams. SETTING: In-season. PARTICIPANTS: A total of 25 male and female elite and subelite athletes from 5 sports. INTERVENTION: 5 × 30-second isometric quadriceps squat exercise using a rigid belt completed over a 4-week period. MAIN OUTCOME MEASURES: (1) single-leg decline squat (SLDS)-a pain provocation test for the patellar tendon (numerical rating score of pain between 0 and 10), (2) VISA-P questionnaire assessing patellar tendon pain and function, and (3) self-reported adherence with completing the exercise over a 4-week period. RESULTS: Baseline SLDS pain was high for these in-season athletes, median 7.5/10 (range 3.5-9) and was significantly reduced over the 4-week intervention (P < 0.001, ES r = 0.580, median change 3.5). VISA-P scores improved after intervention (P < 0.001, ES r = 0.568, mean change 12.2 ± 8.9, percentage mean change 18.8%, where minimum clinical important difference of relative change for VISA-P is 15.4%-27%). Adherence was high; athletes reported completing the exercise 5 times per week. CONCLUSIONS: This pragmatic study suggests that a portable isometric squat reduced pain in-season for athletes with patellar tendinopathy (PT). This form of treatment may be effective, but clinical trials with a control group are needed to confirm the results.

Don't Assume the Control Group Is Normal-People with Asymptomatic Tendon Pathology Have Higher Pressure Pain Thresholds.

Objective: Pain pressure thresholds (PPT) are used to study peripheral and central pain processing. In the tendon, pathological changes may exist without pain. This pilot study aimed to compare PPT between individuals with normal tendons and asymptomatic tendon pathology, and between individuals with and without a history of tendon pain. Methods: The patellar, Achilles, and supraspinatus tendons of 128 asymptomatic participants were examined with ultrasound. Global PPT average was determined using a digital algometer at the patellar tendon, quadriceps muscle, L3 spinous process, and deltoid muscle insertion. Participants were separated into three groups: (1) healthy control group (no pathology, no history of pain), (2) tendon pathology at any site without a history of pain, (3) history of tendon pain anywhere. Results: There were 92 controls, seven with asymptomatic pathology and 29 with a history of tendon pain. Asymptomatic tendon pathology at any site (without a history of pain) was associated with globally increased PPTs compared with controls (P < 0.001, pathology N = 7, N = 92 controls). Matched pair analysis remained significant (P < 0.004). A history of tendon pain was associated with globally increased PPTs compared with the control group (P = 0.026). Matched pair analysis was not significant (P = 0.122). Conclusions: Asymptomatic tendon pathology is associated with higher PPTs. These findings point toward central nervous system adaptations but in a novel way-central desensitization. This challenges the validity of conclusions drawn from PPT studies that do not verify normal structure in the control group; artificial inflation of control group data may incorrectly indicate decreased PPTs in the comparison group.

Nonpharmacological Management of Persistent Pain in Elite Athletes: Rationale and Recommendations.

Persistent pain is common in elite athletes. The current review arose from a consensus initiative by the International Olympic Committee to advance the development of a standardized, scientific, and evidence-informed approach to management. We suggest that optimal management of persistent pain in elite athletes requires an understanding of contemporary pain science, including the rationale behind and implementation of a biopsychosocial approach to care. We argue that athletes and clinicians need to understand the biopsychosocial model because it applies to both pain and the impact of pain with special reference to the sport setting. Management relies on thorough and precise assessment that considers contributing factors across nociceptive, inflammatory, neuropathic, and centrally acting domains; these can include contextual and psychosocial factors. Pain management seeks to remove contributing factors wherever possible through targeted education; adjustment of mechanical loading, training, and performance schedules; psychological therapies; and management of inflammation.

Isometric Contractions Are More Analgesic Than Isotonic Contractions for Patellar Tendon Pain: An In-Season Randomized Clinical Trial.

OBJECTIVE: This study aimed to compare the immediate analgesic effects of 2 resistance programs in in-season athletes with patellar tendinopathy (PT). Resistance training is noninvasive, a principle stimulus for corticospinal and neuromuscular adaptation, and may be analgesic. DESIGN: Within-season randomized clinical trial. Data analysis was conducted blinded to group. SETTING: Subelite volleyball and basketball competitions. PARTICIPANTS: Twenty jumping athletes aged more than 16 years, participating in games/trainings 3 times per week with clinically diagnosed PT. INTERVENTIONS: Two quadriceps resistance protocols were compared; (1) isometric leg extension holds at 60 degrees knee flexion (80% of their maximal voluntary isometric contraction) or (2) isotonic leg extension (at 80% of their 8 repetition maximum) 4 times per week for 4 weeks. Time under load and rest between sets was matched between groups. MAIN OUTCOME MEASURES: (1) Pain (0-10 numerical rating score) during single leg decline squat (SLDS), measured preintervention and postintervention sessions. (2) VISA-P, a questionnaire about tendon pain and function, completed at baseline and after 4 weeks. RESULTS: Twenty athletes with PT (18 men, mean 22.5 ± 4.7 years) participated (isotonic n = 10, isometric n = 10). Baseline median SLDS pain was 5/10 for both groups (isotonic range 1-8, isometric range 2-8). Isometric contractions produced significantly greater immediate analgesia (P < 0.002). Week one analgesic response positively correlated with improvements in VISA-P at 4 weeks (r = 0.64). CONCLUSIONS: Both protocols appear efficacious for in-season athletes to reduce pain, however, isometric contractions demonstrated significantly greater immediate analgesia throughout the 4-week trial. Greater analgesia may increase the ability to load or perform.

Tendon neuroplastic training: changing the way we think about tendon rehabilitation: a narrative review.

Tendinopathy can be resistant to treatment and often recurs, implying that current treatment approaches are suboptimal. Rehabilitation programmes that have been successful in terms of pain reduction and return to sport outcomes usually include strength training. Muscle activation can induce analgesia, improving self-efficacy associated with reducing one's own pain. Furthermore, strength training is beneficial for tendon matrix structure, muscle properties and limb biomechanics. However, current tendon rehabilitation may not adequately address the corticospinal control of the muscle, which may result in altered control of muscle recruitment and the consequent tendon load, and this may contribute to recalcitrance or symptom recurrence. Outcomes of interest include the effect of strength training on tendon pain, corticospinal excitability and short interval cortical inhibition. The aims of this concept paper are to: (1) review what is known about changes to the primary motor cortex and motor control in tendinopathy, (2) identify the parameters shown to induce neuroplasticity in strength training and (3) align these principles with tendon rehabilitation loading protocols to introduce a combination approach termed as tendon neuroplastic training. Strength training is a powerful modulator of the central nervous system. In particular, corticospinal inputs are essential for motor unit recruitment and activation; however, specific strength training parameters are important for neuroplasticity. Strength training that is externally paced and akin to a skilled movement task has been shown to not only reduce tendon pain, but modulate excitatory and inhibitory control of the muscle and therefore, potentially tendon load. An improved understanding of the methods that maximise the opportunity for neuroplasticity may be an important progression in how we prescribe exercise-based rehabilitation in tendinopathy for pain modulation and potentially restoration of the corticospinal control of the muscle-tendon complex.

Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy.

BACKGROUND: Few interventions reduce patellar tendinopathy (PT) pain in the short term. Eccentric exercises are painful and have limited effectiveness during the competitive season. Isometric and isotonic muscle contractions may have an immediate effect on PT pain. METHODS: This single-blinded, randomised cross-over study compared immediate and 45 min effects following a bout of isometric and isotonic muscle contractions. Outcome measures were PT pain during the single-leg decline squat (SLDS, 0-10), quadriceps strength on maximal voluntary isometric contraction (MVIC), and measures of corticospinal excitability and inhibition. Data were analysed using a split-plot in time-repeated measures analysis of variance (ANOVA). RESULTS: 6 volleyball players with PT participated. Condition effects were detected with greater pain relief immediately from isometric contractions: isometric contractions reduced SLDS (mean±SD) from 7.0±2.04 to 0.17±0.41, and isotonic contractions reduced SLDS (mean±SD) from 6.33±2.80 to 3.75±3.28 (p<0.001). Isometric contractions released cortical inhibition (ratio mean±SD) from 27.53%±8.30 to 54.95%±5.47, but isotonic contractions had no significant effect on inhibition (pre 30.26±3.89, post 31.92±4.67; p=0.004). Condition by time analysis showed pain reduction was sustained at 45 min postisometric but not isotonic condition (p<0.001). The mean reduction in pain scores postisometric was 6.8/10 compared with 2.6/10 postisotonic. MVIC increased significantly following the isometric condition by 18.7±7.8%, and was significantly higher than baseline (p<0.001) and isotonic condition (p<0.001), and at 45 min (p<0.001). CONCLUSIONS: A single resistance training bout of isometric contractions reduced tendon pain immediately for at least 45 min postintervention and increased MVIC. The reduction in pain was paralleled by a reduction in cortical inhibition, providing insight into potential mechanisms. Isometric contractions can be completed without pain for people with PT. The clinical implications are that isometric muscle contractions may be used to reduce pain in people with PT without a reduction in muscle strength.