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.

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.

Increasing load carriage and running speed differentially affect the magnitude, variability and coordination patterns of muscle forces.

The study aims to investigate the effects of different loads and speed during running on inter- and intra-individual muscle force amplitudes, variabilities and coordination patterns. Nine healthy participants ran on an instrumentalized treadmill with an empty weight vest at two velocities (2.6 m/s and 3.3 m/s) or while carrying three different loads (4.5, 9.1, 13.6 kg) at 2.6 m/s while kinematics and kinetics were synchronously recorded. The major lower limb muscle forces were estimated using a musculoskeletal model. Muscle force amplitudes and variability, as well as coordination patterns were compared at the group and at the individual level using respectively statistical parametric mapping and covariance matrices combined with multidimensional scaling. Increasing the speed or the load during running increased most of the muscle force amplitudes (p < 0.01). During the propulsion phase, increasing the load increased muscle force variabilities around the ankle joint (modification of standard deviation up to 5% of body weight (BW), p < 0.05) while increasing the speed decreased variability for almost all the muscle forces (up to 10% of BW, p < 0.05). Each runner has a specific muscle force coordination pattern signature regardless of the different experimental conditions (p < 0.05). Yet, this individual pattern was slightly adapted in response to a change of speed or load (p < 0.05). Our results suggest that adding load increases the amplitude and variability of muscle force, but an increase in running speed decreases the variability. These findings may help improve the design of military or trail running training programs and injury rehabilitation by progressively increasing the mechanical load on anatomical structures.

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.

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.

Do the General Public and Health Care Professionals Think That Running Is Bad for the Knees? A Cross-sectional International Multilanguage Online Survey.

Background: Running is a popular sport with widely recognized health benefits. Given the high rates of knee injury in runners and the growing prevalence of knee osteoarthritis (KOA), it may be useful to assess perceptions about running and knee joint health. Purpose: The objectives of this study were to (1) explore and compare the perceptions of the general public (PUB) and health care professionals (HCPs) on the topic of running and knee health and (2) explore recommendations about running and knee health provided by HCPs. Study Design: Cross-sectional study. Methods: We conducted an online survey between June 18 and October 1, 2020. The questionnaire included questions on running and knee health, and HCPs were asked about their typical recommendations and level of confidence in providing recommendations on the topic. Perceptions (proportions) were compared between the PUB and HCPs using the chi-square test. Results: In total, 4521 responses (PUB, n = 2514; HCPs, n = 2007) were analyzed. A greater proportion of HCPs perceived regular running as healthy for knees (86% vs 68%; P < .001). More of the PUB than HCPs (P < .001) believed that running frequently (29% vs 13%), long distances (54% vs 45%), and on hard surfaces (60% vs 36%) increased the risk of developing KOA. Running for those with KOA was perceived by the PUB as posing an increased risk of getting more knee pain (48%) and needing joint replacement surgery (38%), more so than by HCPs (26% and 17%, respectively). The majority of HCPs reported being relatively confident in providing evidence-based recommendations about running and knee health and mostly recommended that runners with KOA modify training parameters instead of quit. Conclusion: More HCPs perceived running as healthy for knees when compared with the PUB. Most HCPs felt confident in providing evidence-based recommendations about running and knee health.

Survey of confidence and knowledge to manage patellofemoral pain in readers versus nonreaders of the physical therapy clinical practice guideline.

OBJECTIVES: To compare beliefs of physical therapists (PTs) who read the clinical practice guideline (CPG) for the management of individuals with patellofemoral pain (PFP) to those who have not read the CPG. DESIGN: Cross-sectional study. SETTING: Online survey. PARTICIPANTS: 494 currently licensed/registered PTs or physiotherapists. MAIN OUTCOME MEASURES: Respondents answered Likert-based or open-ended questions regarding the diagnosis, prognosis, risk factors, and management of individuals with PFP, as well as confidence for managing individuals with PFP, especially the ability to identify beneficial and non-beneficial interventions. We dichotomized responses into participants who read (READERS) and did not read (NonREADERS) the CPG. RESULTS: Most respondents held inaccurate beliefs about risk factors and prognosis; however, READERS' beliefs better aligned with the CPG than NonREADERS (P < 0.01). Most respondents correctly agreed that hip and knee exercise was the recommended treatment strategy; yet NonREADERS believed in implementing unsupported passive treatments (P < 0.01). READERS reported greater confidence in managing individuals with PFP, delivering evidence-based interventions, identifying less beneficial treatments, and locating evidence-based resources than NonREADERS (P < 0.01). CONCLUSION: While READERS and NonREADERS held accurate beliefs for exercise-based treatment for PFP, greater knowledge translation is needed to counter inaccurate beliefs regarding risk factors, prognostic factors, and passive treatments.

Recreational runners with Achilles tendinopathy have clinically detectable impairments: A case-control study.

OBJECTIVES: To confirm what impairments are present in runners with Achilles tendinopathy (AT) and explore the variance of AT severity in an adequately powered study. DESIGN: Case-control study. SETTING: Two private physiotherapy clinics in Australia and Spain. PARTICIPANTS: Forty-four recreational male runners with AT and 44 healthy controls matched by age, height, and weight. MAIN OUTCOME MEASURES: Demographics, activity (IPAQ-SF), pain and function (VISA-A), pain during hopping (Hop pain VAS), hopping duration, psychological factors (TSK-11, PASS20), and physical tests regarding lower-limb maximal strength and endurance. RESULTS: Body mass index (BMI), activity, VISA-A, pain, and duration of hopping, TSK-11, PASS20, standing heel raise to failure, seated heel raise and leg extension 6RM, hip extension and abduction isometric torque were significantly different between groups (P < 0.05) with varied effect sizes (V = 0.22, d range = 0.05-4.18). 46% of AT severity variance was explained by higher BMI (ß = -0.41; p = 0.001), weaker leg curl 6RM (ß = 0.32; p = 0.009), and higher pain during hopping (ß = -0.43; p = 0.001). CONCLUSION: Runners with AT had lower activity levels, lower soleus strength, and were less tall. BMI, pain during hopping, and leg curl strength explained condition severity. This information, identified with clinically applicable tools, may guide clinical assessment, and inform intervention development.

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.

Fear of movement and (re)injury is associated with condition specific outcomes and health-related quality of life in women with patellofemoral pain.

OBJECTIVES: Investigate the association of fear of movement and (re)injury with clinical outcomes in women with patellofemoral pain (PFP). METHODS: This cross-sectional study included 92 women with PFP who completed the TAMPA scale for kinesiophobia. The TAMPA score and its two subscales - activity avoidance and somatic focus were correlated with BMI, physical activity level, pain catastrophizing scale, health-related quality of life, pain sensitivity via pressure pain threshold, self-reported disability, and worst knee pain in last month. RESULTS: Greater fear of movement and (re)injury, activity avoidance, and somatic focus were correlated with lower local pain sensitivity (rho = -0.29 to -0.55), lower health-related quality of life (rho = -0.38 to -0.42), greater pain catastrophizing (rho = 0.41 to 0.47), and greater self-reported disability (rho = -0.31 to -0.52). Greater fear of movement and (re)injury and activity avoidance were correlated with adjacent and remote pain sensitivity (rho = -0.24 to -0.39). Greater fear of movement and (re)injury and somatic focus were correlated with greater worst knee pain in last month (rho = 0.21 to 0.32). Fear of movement and (re)injury predicted pain measures, disability, and health-related quality of life (p ≤ 0.010). CONCLUSION: The relationship of greater fear of movement and (re)injury with greater disability, pain catastrophizing, pain sensitization, and poorer health-related quality of life highlights the potential importance of considering this psychological feature of PFP during assessment and management.

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.

Peak and Per-Step Tibial Bone Stress During Walking and Running in Female and Male Recreational Runners.

BACKGROUND: Athletes, especially female athletes, experience high rates of tibial bone stress injuries (BSIs). Knowledge of tibial loads during walking and running is needed to understand injury mechanisms and design safe running progression programs. PURPOSE: To examine tibial loads as a function of gait speed in male and female runners. STUDY DESIGN: Controlled laboratory study. METHODS: Kinematic and kinetic data were collected on 40 recreational runners (20 female, 20 male) during 4 instrumented gait speed conditions on a treadmill (walk, preferred run, slow run, fast run). Musculoskeletal modeling, using participant-specific magnetic resonance imaging and motion data, was used to estimate tibial stress. Peak tibial stress and stress-time impulse were analyzed using 2-factor multivariate analyses of variance (speed*sex) and post hoc comparisons (α = .05). Bone geometry and tibial forces and moments were examined. RESULTS: Peak compression was influenced by speed (P < .001); increasing speed generally increased tibial compression in both sexes. Women displayed greater increases in peak tension (P = .001) and shear (P < .001) than men when transitioning from walking to running. Further, women displayed greater peak tibial stress overall (P < .001). Compressive and tensile stress-time impulse varied by speed (P < .001) and sex (P = .006); impulse was lower during running than walking and greater in women. A shear stress-time impulse interaction (P < .001) indicated that women displayed greater impulse relative to men when changing from a walk to a run. Compared with men, women displayed smaller tibiae (P < .001) and disproportionately lower tibial forces (P≤ .001-.035). CONCLUSION: Peak tibial stress increased with gait speed, with a 2-fold increase in running relative to walking. Women displayed greater tibial stress than men and greater increases in stress when shifting from walking to running. Sex differences appear to be the result of smaller bone geometry in women and tibial forces that were not proportionately lower, given the womens' smaller stature and lower mass relative to men. CLINICAL RELEVANCE: These results may inform interventions to regulate running-related training loads and highlight a need to increase bone strength in women. Lower relative bone strength in women may contribute to a sex bias in tibial BSIs, and female runners may benefit from a slower progression when initiating a running program.

Optimal Load for Managing Low-Risk Tibial and Metatarsal Bone Stress Injuries in Runners: The Science Behind the Clinical Reasoning.

BACKGROUND: Low-risk bone stress injuries (BSIs) of the tibia and metatarsal diaphyses account for more than half of BSIs in runners. They interrupt training and are managed using noninvasive approaches that are designed to achieve a speedy but safe return to running. CLINICAL QUESTION: What is the optimal load to manage low-risk tibial and metatarsal BSIs and safely return to running? KEY RESULTS: Optimal load can be guided by knowledge of the BSI healing process and is symptom driven. At all stages, the optimal load does not produce symptoms during, after, or the day following loading. CLINICAL APPLICATION: A period of initial load reduction, via partial or non-weight bearing, is typically needed to alleviate presenting symptoms. Analgesics or nonsteroidal anti-inflammatory drugs may be used in the short term (sooner than 7 days), but only for resting pain and night pain. Healing supplements (eg, low-intensity pulsed ultrasound and/or recombinant parathyroid hormone therapy) may be attempted to influence tissue healing. Athletes can maintain cardiopulmonary fitness via cross-training, while simultaneously addressing musculoskeletal fitness. A return-to-run program can be initiated once an athlete is pain free during daily activities for 5 consecutive days. Progress is directed by symptom provocation and initially focuses on increasing running volume before speed. Optimal loading should be continued following return to running and may include jump training and/or gait retraining to reduce subsequent BSI risk. The optimal loading approach to managing low-risk tibial and metatarsal BSIs is clinically successful, but requires further scientific validation. J Orthop Sports Phys Ther 2021;51(7):322-330. Epub 7 May 2021. doi:10.2519/jospt.2021.9982.

The Effect of Footwear, Running Speed, and Location on the Validity of Two Commercially Available Inertial Measurement Units During Running.

Introduction: Most running-related injuries are believed to be caused by abrupt changes in training load, compounded by biomechanical movement patterns. Wearable technology has made it possible for runners to quantify biomechanical loads (e.g., peak positive acceleration; PPA) using commercially available inertial measurement units (IMUs). However, few devices have established criterion validity. The aim of this study was to assess the validity of two commercially available IMUs during running. Secondary aims were to determine the effect of footwear, running speed, and IMU location on PPA. Materials and Methods: Healthy runners underwent a biomechanical running analysis on an instrumented treadmill. Participants ran at their preferred speed in three footwear conditions (neutral, minimalist, and maximalist), and at three speeds (preferred, +10%, -10%) in the neutral running shoes. Four IMUs were affixed at the distal tibia (IMeasureU-Tibia), shoelaces (RunScribe and IMeasureU-Shoe), and insole (Plantiga) of the right shoe. Pearson correlations were calculated for average vertical loading rate (AVLR) and PPA at each IMU location. Results: The AVLR had a high positive association with PPA (IMeasureU-Tibia) in the neutral and maximalist (r = 0.70-0.72; p ≤ 0.001) shoes and in all running speed conditions (r = 0.71-0.83; p ≤ 0.001), but low positive association in the minimalist (r = 0.47; p < 0.05) footwear condition. Conversely, the relationship between AVLR and PPA (Plantiga) was high in the minimalist (r = 0.75; p ≤ 0.001) condition and moderate in the neutral (r = 0.50; p < 0.05) and maximalist (r = 0.57; p < 0.01) footwear. The RunScribe metrics demonstrated low to moderate positive associations (r = 0.40-0.62; p < 0.05) with AVLR across most footwear and speed conditions. Discussion: Our findings indicate that the commercially available Plantiga IMU is comparable to a tibia-mounted IMU when acting as a surrogate for AVLR. However, these results vary between different levels of footwear and running speeds. The shoe-mounted RunScribe IMU exhibited slightly lower positive associations with AVLR. In general, the relationship with AVLR improved for the RunScribe sensor at slower speeds and improved for the Plantiga and tibia-mounted IMeasureU sensors at faster speeds.

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.