Are Physical Function and Fear of Movement Risk Factors for Patellofemoral Pain? A 2-Year Prospective Study.

CONTEXT: To determine (1) whether physical function and fear of movement are prospectively associated with the risk of females developing patellofemoral pain (PFP) and (2) whether they change following development of PFP. DESIGN: Prospective observational study. METHODS: A total of 114 asymptomatic females (18-22 y old) completed assessment of physical function (forward step-down test and single-leg hop for distance) and fear of movement using the Tampa Scale for Kinesiophobia at baseline and 2-year follow-up. Presence of symptoms of PFP was monitored bimonthly. RESULTS: Ninety participants (retention rate = 79%) completed the 2-year follow-up assessment, with 27 (24% of the cohort) developing PFP. Physical function, including forward step-down test (P = .659) and single-leg hop for distance (P = .825), and fear of movement (P = .479) were not associated with the risk of developing PFP. Females who developed PFP presented with reduced forward step-down repetitions (mean difference = 2.8; 95% confidence interval, 0.2 to 5.3) and single-leg hop for distance (10.2; 95% confidence interval, 2.7 to 17.7 cm) at 2-year follow-up. There was no statistically significant difference between those who did and did not develop PFP for fear of movement (-3.4; 95% confidence interval, -7.0 to 0.2). CONCLUSIONS: Physical function and fear of movement were not associated with the risk of developing PFP in young females. However, the change over time in the step-down and single-leg hop for distance tests may suggest that, even in the early stages of PFP, young females present impaired physical function compared with females who did not develop symptoms. Fear of movement may develop due to persistent PFP, and does not appear to be a risk factor or key feature in females with PFP of short symptoms duration.

Tendon loading in runners with Achilles tendinopathy: Relations to pain, structure, and function during return-to-sport.

We aimed to (1) compare pain, tendon structure, lower limb function, and Achilles tendon loads while running between limbs in runners with Achilles tendinopathy, and (2) explore the relations of pain, tendon structure, and lower limb function to Achilles tendon loads while running. Twenty runners with Achilles tendinopathy participated in this pilot study. Pain was assessed with questionnaires, quantitative sensory testing, and functional testing. Tendon morphology and mechanical properties were evaluated with ultrasound imaging, continuous shear wave elastography, and ultrasound imaging combined with dynamometry. Lower limb function was assessed with an established test battery. Achilles tendon loads were estimated from biomechanical data acquired during running. Compared to the least symptomatic limb, the most symptomatic limb had lower scores on the Victorian Institute of Sports Assessment - Achilles questionnaire and worse pain during drop countermovement jumping, hopping, and running. Tendon thickness and cross-sectional area were greater, and Young's modulus, drop countermovement jump height, and plyometric quotient during hopping were lower on the most symptomatic limb. Side-to-side differences in drop countermovement jump height were significantly associated with side-to-side differences in Achilles tendon peak forces and average loading rates during running. Various measures of pain, structure, and function differ between limbs in runners with Achilles tendinopathy during return-to-sport. Tendon forces, however, do not differ between limbs during comfortable running. In addition to measures that differ between limbs, measures of performance during drop countermovement jumping may aid in clinical decision-making during return-to-sport because they are associated with tendon forces while running.

Oxford consensus on primary cam morphology and femoroacetabular impingement syndrome: part 1-definitions, terminology, taxonomy and imaging outcomes.

INTRODUCTION: Primary cam morphology is a mostly benign bony prominence that develops at the femoral head-neck junction of the hip, but it is highly prevalent in many athlete populations. In the small proportion of athletes for whom it is not benign, the resulting hip osteoarthritis can be debilitating. Clinicians, athletes, patients and researchers do not yet agree on important primary cam morphology elements. We aimed to ascertain and improve the level of agreement on primary cam morphology definitions, terminology, taxonomy and imaging outcome measures. METHODS: To collect and aggregate informed opinions, an expert panel-the Young Athlete's Hip Research Collaborative-rated primary cam morphology definition, terminology, taxonomy and imaging outcome statements through an online Delphi exercise followed by an online meeting to explore areas of tension and dissent. Reporting followed Conducting and REporting DElphi Studies. RESULTS: A diverse and inclusive Delphi panel (n=65 for rounds 1 and 2, representing 18 countries; 6 stakeholder groups; 40% women) agreed on 35 of 47 statements in 4 domains, while surfacing areas of tension and dissent. This Delphi panel agreed on four key issues essential to moving research and clinical care forward around primary cam morphology. They agreed on: (1) definition, confirming its conceptual attributes (tissue type, size, location, shape and ownership); (2) terminology-use 'morphology' and not terms with a negative connotation like 'lesion', 'abnormality' or 'deformity'; (3) taxonomy, distinguishing between primary and secondary cam morphology, and (4) imaging outcomes, a continuous bone/cartilage alpha angle on radial femoral head-neck MRI for primary cam morphology aetiology research. CONCLUSION: This consensus provides athletes, patients, clinicians and researchers with a strong foundation to guide more precise communication, better clinical decision-making and higher value research about primary cam morphology and its natural history.

Oxford consensus on primary cam morphology and femoroacetabular impingement syndrome: part 2-research priorities on conditions affecting the young person's hip.

INTRODUCTION: Primary cam morphology is highly prevalent in many athlete populations, causing debilitating hip osteoarthritis in some. Existing research is mired in confusion partly because stakeholders have not agreed on key primary cam morphology elements or a prioritised research agenda. We aimed to inform a more rigorous, inclusive and evidence-based approach to research on primary cam morphology and its natural history by working towards agreement on a set of research priorities for conditions affecting the young person's hip. METHODS: An international expert panel-the Young Athlete's Hip Research (YAHiR) Collaborative-rated research priority statements through an online two-round Delphi exercise and met online to explore areas of tension and dissent. Panellists ranked the prioritised research statements according to the Essential National Health Research (ENHR) ranking strategy. Reporting of results followed REPRISE (REporting guideline for PRIority SEtting of health). RESULTS: A diverse Delphi panel (n=65, Delphi rounds 1 and 2; three ENHR strategy surveys: n=49; n=44; n=42) from 18 countries representing six stakeholder groups, prioritised and ranked 18 of 38 research priority statements. The prioritised statements outlined seven research domains: (1) best practice physiotherapy, (2) rehabilitation progression and return to sport, (3) exercise intervention and load management, (4) primary cam morphology prognosis and aetiology, (5) femoroacetabular impingement syndrome prognosis and aetiology, (6) diagnostic criteria, and (7) screening. The panel recommended areas of tension and dissent for the research community to focus on immediately. CONCLUSION: While informing more rigorous, inclusive and evidence-based research, this consensus is a roadmap for researchers, policy-makers and funders to implement research dedicated to reducing the cost and burden of hip disease related to primary cam morphology.

Preventing Bone Stress Injuries in Runners with Optimal Workload.

Bone stress injuries (BSIs) occur at inopportune times to invariably interrupt training. All BSIs in runners occur due to an "error" in workload wherein the interaction between the number and magnitude of bone tissue loading cycles exceeds the ability of the tissue to resist the repetitive loads. There is not a single optimal bone workload, rather a range which is influenced by the prevailing scenario. In prepubertal athletes, optimal bone workload consists of low-repetitions of fast, high-magnitude, multidirectional loads introduced a few times per day to induce bone adaptation. Premature sports specialization should be avoided so as to develop a robust skeleton that is structurally optimized to withstand multidirectional loading. In the mature skeleton, optimal workload enables gains in running performance but minimizes bone damage accumulation by sensibly progressing training, particularly training intensity. When indicated (e.g., following repeated BSIs), attempts to reduce bone loading magnitude should be considered, such as increasing running cadence. Determining the optimal bone workload for an individual athlete to prevent and manage BSIs requires consistent monitoring. In the future, it may be possible to clinically determine bone loads at the tissue level to facilitate workload progressions and prescriptions.

Pain and disability in women with patellofemoral pain relate to kinesiophobia, but not to patellofemoral joint loading variables.

BACKGROUND: Altered patellofemoral joint (PFJ) loading and elevated kinesiophobia are commonly reported in people with patellofemoral pain (PFP). However, the relative relationship of these physical-psychological variables with pain and disability in people with PFP is unknown. AIM: To explore the relationship of PFJ loading during stair ascent and kinesiophobia, with self-reported pain and disability in women with PFP. METHODS: Fifty-seven women with PFP completed the Tampa Scale for Kinesiophobia, a Visual Analog Scale (0-100 mm) for pain during stair ascent, and the Anterior Knee Pain Scale (disability). Stair ascent mechanics were assessed via three-dimensional motion analysis while participants ascended an instrumented seven-step staircase. Peak PFJ contact force and stress, and PFJ contact force and stress loading rates were estimated using a musculoskeletal model. The relationships of PFJ kinetics during stair ascent and kinesiophobia, with the Anterior Knee Pain Scale (disability) and pain during stair ascent, were evaluated with Spearman rank correlation. Variables (kinetics and kinesiophobia) significantly correlating with the dependent variables (pain and disability) were inserted in linear regression models. RESULTS: Kinesiophobia was moderately associated with self-reported pain (rho = 0.37) and disability (rho = -0.58) in women with PFP. No PFJ loading variables were found to be associated with self-reported pain or disability (P > .05). Kinesiophobia explained 14% of the variance of participants' pain while ascending stairs and 33% of the variance of participant's self-reported disability. CONCLUSION: Addressing kinesiophobia during treatment of women with PFP may be important to reduce self-reported pain and disability.

Use of Wearables: Tracking and Retraining in Endurance Runners.

Wearable devices are ubiquitous among runners, coaches, and clinicians with an ever-increasing number of devices coming on the market. In place of gold standard measures in the laboratory, these devices attempt to provide a surrogate means to track running biomechanics outdoors. This review provides an update on recent literature in the field of wearable devices in runners, with an emphasis on criterion validity and usefulness in the coaching and rehabilitation of runners. Our review suggests that while enthusiasm should be tempered, there is still much for runners to gain with wearables. Overall, our review finds evidence supporting the use of wearables to improve running performance, track global training loads applied to the runner, and provide real-time feedback on running speed and run cadence. Case studies illustrate the use of wearables for the purposes of performance and rehabilitation.

Independent effects of step length and foot strike pattern on tibiofemoral joint forces during running.

The purpose of this study was to examine the effects of step length and foot strike pattern along with their interaction on tibiofemoral joint (TFJ) and medial compartment TFJ kinetics during running. Nineteen participants ran with a rear foot strike pattern at their preferred speed using a short (-10%), preferred, and long (+10%) step length. These step length conditions were then repeated using a forefoot strike pattern. Regardless of foot strike pattern, a 10% shorter step length resulted in decreased peak contact force, force impulse per step, force impulse per kilometre, and average loading rate at the TFJ and medial compartment, while a 10% increased step length had the opposite effects (all P < 0.05). A forefoot strike pattern significantly lowered TFJ and medial compartment TFJ average loading rates compared with a rear foot strike pattern (both <0.05) but did not change TFJ or medial compartment peak force, force impulse per step, or force impulse per km. The combination of a shorter step length and forefoot strike pattern produced the greatest reduction in peak medial compartment contact force (P < 0.05). Knowledge of these running modification effects may be relevant to the management or prevention of TFJ injury or pathology among runners.

Changes in tibiofemoral contact forces during running in response to in-field gait retraining.

We evaluated the efficacy of an in-field gait retraining programme using mobile biofeedback to reduce cumulative and peak tibiofemoral loads during running. Thirty runners were randomised to either a retraining group or control group. Retrainers were asked to increase their step rate by 7.5% over preferred in response to real-time feedback provided by a wrist mounted running computer for 8 routine in-field runs. An inverse dynamics driven musculoskeletal model estimated total and medial tibiofemoral joint compartment contact forces. Peak and impulse per step total tibiofemoral contact forces were immediately reduced by 7.6% and 10.6%, respectively (P < 0.001). Similarly, medial tibiofemoral compartment peak and impulse per step tibiofemoral contact forces were reduced by 8.2% and 10.6%, respectively (P < 0.001). Interestingly, no changes were found in knee adduction moment measures. Post gait retraining, reductions in medial tibiofemoral compartment peak and impulse per step tibiofemoral contact force were still present (P < 0.01). At the 1-month post-retraining follow-up, these reductions remained (P < 0.05). With these per stance reductions in tibiofemoral contact forces in mind, cumulative tibiofemoral contact forces did not change due to the estimated increase in number of steps to run 1 km.

Validity of a commercially available load cell dynamometer in measuring isometric knee extension torque in patients with knee disorders.

OBJECTIVE: Assess the validity of hand-held dynamometry (HHD) and the Tindeq Progressor (TP) in assessing peak isometric knee extension torque and limb symmetry index (LSI) versus isokinetic dynamometer (IKD). DESIGN: Prospective cross-sectional study. SETTING: Laboratory. PARTICIPANTS: 31 individuals with unilateral knee disorders (21 female; 28.3 ± 11 years). MAIN OUTCOME MEASURES: Peak isometric knee extension torque; Knee extension LSI. RESULTS: Strong to almost perfect (p < 0.001) correlations (Cohen's Kappa k) with IKD were found for both devices for peak torque of the uninvolved limb (HHD [k = 0.84], TP [k = 0.91]) and involved limb (HHD [k = 0.93], TP [k = 0.98]). For LSI, moderate to strong (p < 0.001) correlations with IKD were found for HHD (k = 0.79) and TP (k = 0.89). Mean bias errors were equivalent for determining LSI (HHD = 0.02%; TP = 0.03%). Both HHD and TP were highly sensitive (96.2-100.0%) and specific (100.0%) at the 70% LSI threshold. TP showed higher sensitivity and specificity at the 90% LSI threshold. CONCLUSION: HHD and TP are valid in measuring isometric knee extension torque with the reference standard IKD. TP showed superior validity in identifying LSI. TP also shows greater specificity in identifying the 90% LSI threshold.

Is the addition of running retraining to best standard care beneficial in runners with medial tibial stress syndrome? Protocol for a randomised controlled trial.

BACKGROUND: Running retraining is commonly used in the management of medial tibial stress syndrome (MTSS) but evidence for its effectiveness is lacking. The primary aim of this study is to determine if the addition of running retraining to best standard care is beneficial in the management of runners with MTSS. METHODS: This study is an assessor-blinded and participant-blinded, parallel-group, randomised controlled trial. The trial will recruit 64 participants aged between 18 and 45 years, with a clinical diagnosis of MTSS that has affected their running participation for at least four weeks. Participants will be randomised to receive best standard care (control) or running retraining and best standard care (intervention group) over an 8-week period. Best standard care will consist of load management advice, symptom management advice, footwear advice and a strengthening program. Running retraining will consist of a cue to reduce running step length. Outcomes will be measured at weeks 1, 2, 4 and 8. The primary outcome measure will be the University of Wisconsin Running Injury and Recovery Index at week 4. Secondary outcome measures include: (i) Exercise Induced Leg Pain Questionnaire-British Version, (ii) global rating of change scale, (iii) worst pain experienced during a run, (iv) weekly run volume, (v) reactive strength index score, (vi) single leg hop test, (vii) soleus single leg maximum voluntary isometric contraction, (viii) gastrocnemius single leg maximum voluntary isometric contraction, (ix) single leg plantar flexor endurance test, (x) running step length, and (xi) running step rate. Data will be analysed using the intention-to-treat principle. DISCUSSION: This randomised controlled trial will evaluate if reducing running step length provides additional benefit to best standard care in the management of runners with MTSS over an 8-week period. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12624000230550.

Current practice, guideline adherence, and barriers to implementation for Achilles tendinopathy rehabilitation: a survey of physical therapists and people with Achilles tendinopathy.

Objective: To explore clinical practice patterns of physical therapists (PTs) who treat people with Achilles tendinopathy (AT), and identify perceived barriers and facilitators for prescribing and engaging with therapeutic exercise among PTs and people with AT. Methods: Two cross-sectional surveys were electronically distributed between November 2021 and May 2022; one survey was designed for PTs while the second was for people with AT. Survey respondents answered questions regarding their physical therapy training and current practice (PTs), injury history and management (people with AT), and perceived barriers and facilitators (PTs and people with AT). Results: 341 PTs and 74 people with AT completed the surveys. In alignment with clinical practice guidelines, more than 94% of PTs surveyed (97% of whom had some form of advanced musculoskeletal training) prioritise patient education and therapeutic exercise. Patient compliance, patient knowledge, and the slow nature of recovery were barriers to prescribing therapeutic exercise reported by PTs, while time, physical resources, and a perceived lack of short-term treatment effectiveness were barriers for people with AT. Conclusions: Consistent with clinical practice guidelines, PTs with advanced training reported prioritising therapeutic exercise and education for managing AT. However, both PTs and people with AT identified many barriers to prescribing or engaging with therapeutic exercise. By addressing misconceptions about the time burden and ineffectiveness of exercise, and by overcoming access issues to exercise space and equipment, PTs may be able to improve intervention adherence and subsequently outcomes for people with AT.

Achilles tendon forces and pain during common rehabilitation exercises in male runners with Achilles tendinopathy. A laboratory study.

OBJECTIVES: To estimate Achilles tendon forces and their relationship with self-reported pain in runners with Achilles tendinopathy (AT) during common rehabilitation exercises. DESIGN: Cross-sectional. SETTING: Laboratory. PARTICIPANTS: 24 recreational male runners (45.92 (8.24) years old; 78.20 (8.01) kg; 177.17 (6.69) cm) with symptomatic AT. MAIN OUTCOME MEASURES: Kinematic and kinetic data were collected to estimate Achilles tendon forces during 12 commonly prescribed exercises. Achilles tendon forces were estimated from biomechanical data and normalised to the participant's bodyweight. The secondary aim was to investigate the relationship between Achilles tendon forces and pain during these exercises. RESULTS: Two exercise clusters were identified based on Achilles tendon forces. Cluster1 included various exercises including double heel raises, single heel raises, and walking (range: 1.10-2.76 BWs). Cluster2 included running, jumping and hopping exercises (range: 5.13-6.35 BWs). Correlation between tendon forces and pain was at best low for each exercise (range: -0.43 - 0.20). Higher force exercises lead to more tendon load for a given amount of pain (R2 = 0.7505; y = 0.2367x + 0.6191). CONCLUSION: This study proposes a hierarchical exercise progression based on Achilles tendon forces to guide treatment of runners with AT. Achilles tendon forces and pain are not correlated in runners with AT.