Trail running injury risk factors: a living systematic review.

OBJECTIVE: To review and frequently update the available evidence on injury risk factors and epidemiology of injury in trail running. DESIGN: Living systematic review. Updated searches will be done every 6 months for a minimum period of 5 years. DATA SOURCES: Eight electronic databases were searched from inception to 18 March 2021. ELIGIBILITY CRITERIA: Studies that investigated injury risk factors and/or reported the epidemiology of injury in trail running. RESULTS: Nineteen eligible studies were included, of which 10 studies investigated injury risk factors among 2 785 participants. Significant intrinsic factors associated with injury are: more running experience, level A runner and higher total propensity to sports accident questionnaire (PAD-22) score. Previous history of cramping and postrace biomarkers of muscle damage is associated with cramping. Younger age and low skin phototypes are associated with sunburn. Significant extrinsic factors associated with injury are neglecting warm-up, no specialised running plan, training on asphalt, double training sessions per day and physical labour occupations. A slower race finishing time is associated with cramping, while more than 3 hours of training per day, shade as the primary mode of sun protection and being single are associated with sunburn. An injury incidence range 0.7-61.2 injuries/1000 hours of running and prevalence range 1.3% to 90% were reported. The lower limb was the most reported region of injury, specifically involving blisters of the foot/toe. CONCLUSION: Limited studies investigated injury risk factors in trail running. Our review found eight intrinsic and nine extrinsic injury risk factors. This review highlighted areas for future research that may aid in designing injury risk management strategies for safer trail running participation.PROSPERO registration numberCRD42021240832.

Epidemiology of Injury and Illness Among Trail Runners: A Systematic Review.

BACKGROUND: Trail running is characterised by large elevation gains/losses and uneven varying running surfaces. Limited information is available on injury and illness among trail runners to help guide injury and illness prevention strategies. OBJECTIVE: The primary aim of this review was to describe the epidemiology of injury and illness among trail runners. METHODS: Eight electronic databases were systematically searched (MEDLINE Ovid, PubMed, Scopus, SportsDiscus, CINAHL, Health Source: Nursing/Academic, Health Source: Consumer Ed., and Cochrane) from inception to November 2020. The search was conducted according to the PRISMA statement and the study was registered on PROSPERO international prospective register of systematic reviews (CRD42019135933). Full-text English and French studies that investigated injury and/or illness among trail runners participating in training/racing were included. The main outcome measurements included: trail running injury (incidence, prevalence, anatomical site, tissue type, pathology-type/specific diagnosis, severity), and illness (incidence, prevalence, symptoms, specific diagnosis, organ system, severity). The methodological quality of the included studies was assessed using an adapted Downs and Black assessment tool. RESULTS: Sixteen studies with 8644 participants were included. Thirteen studies investigated race-related injury and/or illness and three studies included training-related injuries. The overall incidence range was 1.6-4285.0 injuries per 1000 h of running and 65.0-6676.6 illnesses per 1000 h of running. The foot was the most common anatomical site of trail running injury followed by the knee, lower leg, thigh, and ankle. Skin lacerations/abrasions were the most common injury diagnoses followed by skin blisters, muscle strains, muscle cramping, and ligament sprains. The most common trail running illnesses reported related to the gastro-intestinal tract (GIT), followed by the metabolic, and cardiovascular systems. Symptoms of nausea and vomiting related to GIT distress and dehydration were commonly reported. CONCLUSION: Current trail running literature consists mainly of injury and illness outcomes specifically in relation to single-day race participation events. Limited evidence is available on training-related injury and illness in trail running. Our review showed that injury and illness are common among trail runners, but certain studies included in this review only focused on dermatological injuries (e.g. large number of feet blisters) and GIT symptoms. Specific areas for future research were identified that could improve the management of trail running injury and illness.

Asymmetrical loading demands associated with vertical jump landings in people with unilateral transtibial amputation.

Loading symmetry during vertical jump landings between a person with amputation's intact and prosthetic limbs was assessed to determine the role of each limb in controlling the downward momentum of the center of mass during landing. Six participants with unilateral transtibial amputation (TTA) and ten nondisabled participants completed 10 maximal vertical jumps, of which the highest jump was analyzed. Contralateral symmetry was assessed through the Symmetry Index (SI), while symmetry at the group level was assessed through a Mann-Whitney U test. Participants with TTA performed quasi-unilateral landings onto the intact limbs, resulting from either the incapability of the prosthetic ankle to plantar flex or increased residual-limb knee and hip flexion. In the loading phase, the participants with TTA displayed reduced prosthetic-side peak vertical forces (p = 0.04) along with reduced prosthetic-side ankle range of motion (p < 0.001), extensor moments (p = 0.03), and negative work generated (p = 0.00). Individual asymmetries were evident in the peak vertical force magnitudes (SI = 51%-140%), duration from touchdown to peak vertical force (SI = 52%-157%), ankle joint angles at touchdown (SI = 100%-538%), ranges of motion (SI = 147%-200%), knee (SI = 66%-179%) and hip (SI = 87%-132%) extensor moments, and work done at the ankle (SI = 155%-199%) and hip (SI = 83%-204%). High peak forces (25.25 +/- 4.89 N·kg(-1) intact limb and 14.61 +/- 8.28 N·kg(-1) prosthetic limb) from significantly lower (p < 0.001) landing heights than the nondisabled participants indicate a potential injury risk associated with landing for people with TTA.

Mechanisms to absorb load in amputee running.

BACKGROUND: We aimed to determine if a shock absorbing pylon (SAP) influenced the ground reaction force characteristics and the shock absorbing mechanisms compared to a rigid pylon (Rigid) during the loading phase in running. OBJECTIVES: To determine if the SAP influences the mechanisms of loading compared to the Rigid condition. STUDY DESIGN: A convenience sample of transtibial amputees participated in a laboratory-based study. The prosthetic set-up was randomly altered fd\sdsd. METHODS: Five recreationally active male transtibial amputees age: 18-50 years; mean mass: 86.7 ± 17.5 kg; height: 1.77 ± 0.07 m) volunteered from a population-based sample. They completed a within-participant-designed study assessing a SAP and a Rigid condition during running. Kinematic and kinetic data were collected during two sessions following a one-week customization period. RESULTS: Loading rate, peak vertical and horizontal ground reaction forces and the time to each measure along with knee and hip angular displacement, absorbing powers and work done between the SAP and Rigid conditions were not systematically affected by the prosthetic condition. CONCLUSIONS: The effect of the SAP was minimal and inconsistent in the loading phase, with only some amputees presenting higher and others with lower values for the tested variables.

Kinetic and kinematic compensations in amputee vertical jumping.

A unilateral transtibial amputation causes a disruption to the musculoskeletal system, which results in asymmetrical biomechanics. The current study aimed to assess the movement asymmetry and compensations that occur as a consequence of an amputation when performing a countermovement vertical jump. Six unilateral transtibial amputees and 10 able-bodied (AB) participants completed 10 maximal vertical jumps, and the highest jump was analyzed further. Three-dimensional lower limb kinematics and normalized (body mass) kinetic variables were quantified for the intact and prosthetic sides. Symmetry was assessed through the symmetry index (SI) for each individual and statistically using the Mann-Whitney U test between the intact and prosthetic sides for the amputee group. A descriptive analysis between the amputee and AB participants was conducted to explore the mechanisms of amputee jumping. The amputee jump height ranged from 0.09 to 0.24 m. In the countermovement, all ankle variables were asymmetrical (SI > 10%) and statistically different (p < .05) for the amputees. At the knee and hip, there was no statistical difference between the intact and prosthetic sides range of motion, although there was evidence of individual asymmetry. The knees remained more extended compared with the AB participants to prevent collapse. In propulsion, the prosthesis did not contribute to the work done and the ankle variables were asymmetrical (p < .05). The knee and hip variables were not statistically different between the intact and prosthetic sides, although there was evidence of functional asymmetry and the contribution tended to be greater on the intact compared with the prosthetic side. The lack of kinetic involvement of the prosthetic ankle and both knees due to the limitation of the prosthesis and the altered musculoskeletal mechanics of the joints were the reason for the reduced height jumped.