Daniel Ramskov

High eccentric hip abduction strength reduces the risk of developing patellofemoral pain among novice runners initiating a self-structured running program: a 1-year observational study

STUDY DESIGN Observational prospective cohort study with 1-year follow-up. OBJECTIVES To investigate the relationship between eccentric hip abduction strength and the development of patellofemoral pain (PFP) in novice runners during a self-structured running regime. BACKGROUND Recent research indicates that gluteal muscle weakness exists in individuals with PFP. However, current prospective research has been limited to the evaluation of isometric strength, producing inconsistent findings. Considering that hip muscles, including the gluteus maximus and medius, activate eccentrically to control hip and pelvic motion during weight-bearing activities such as running, the potential link between eccentric strength and PFP risk should be evaluated. METHODS Eight hundred thirty-two novice runners were included at baseline, and 629 participants were included in the final analysis. Maximal eccentric hip abduction strength was measured using a handheld dynamometer prior to initiating a self-structured running program. The diagnostic criteria to classify knee pain as PFP were based on a thorough clinical examination. Participants were followed for 12 months and training characteristics were gathered with a global positioning system. RESULTS Results from the unadjusted generalized linear regression model for cumulative risk at 25 and 50 km indicated differences in cumulative risk of PFP between high strength, normal strength, and low strength (P<.05), with higher strength associated with reduced risk. CONCLUSION Findings from this study indicate that, among novice runners, a level of peak eccentric hip abduction strength that is higher than normal may reduce the risk of PFP during the first 50 km of a self-structured running program.

Diagnoses and time to recovery among injured recreational runners in the RUN CLEVER trial

Purpose The purpose of the present study was to describe the incidence proportion of different types of running-related injuries (RRI) among recreational runners and to determine their time to recovery. Methods A sub-analysis of the injured runners included in the 839-person, 24-week randomized trial named Run Clever. During follow-up, the participants reported levels of pain in different anatomical areas on a weekly basis. In case injured, runners attended a clinical examination at a physiotherapist, who provided a diagnosis, e.g., medial tibial stress syndrome (MTSS), Achilles tendinopathy (AT), patellofemoral pain (PFP), iliotibial band syndrome (ITBS) and plantar fasciopathy (PF). The diagnose-specific injury proportions (IP) and 95% confidence intervals (CI) were calculated using descriptive statistics. The time to recovery was defined as the time from the first registration of pain until total pain relief in the same anatomical area. It was reported as medians and interquartile range (IQR) if possible. Results A total of 140 runners were injured at least once leading to a 24-week cumulative injury proportion of 32% [95% CI: 26%; 37%]. The diagnoses with the highest incidence proportion were MTSS (IP = 16% [95% CI: 9.3%; 22.9%], AT (IP = 8.9% [95% CI: 3.6%; 14.2%], PFP (IP = 8% [95% CI: 3.0%; 13.1%]. The median time to recovery for all types of injuries was 56 days (IQR = 70 days). Diagnose-specific time-to-recoveries included 70 days (IQR = 89 days) for MTSS, 56 days (IQR = 165 days) for AT, 49 days (IQR = 63 days) for PFP. Conclusion The most common running injuries among recreational runners were MTSS followed by AT, PFP, ITBS and PF. In total, 77 injured participants recovered their RRI and the median time to recovery for all types of injuries was 56 days and MTSS was the diagnosis with the longest median time to recovery, 70 days.

Progression in Running Intensity or Running Volume and the Development of Specific Injuries in Recreational Runners: Run Clever, a Randomized Trial Using Competing Risks

BACKGROUND: It has been proposed that training intensity and training volume are associated with specific running‐related injuries. If such an association exists, secondary preventive measures could be initiated by clinicians, based on symptoms of a specific injury diagnosis. OBJECTIVES: To test the following hypotheses: (1) a running schedule focusing on running intensity (S‐I) would increase the risk of sustaining Achilles tendinopathy, gastrocnemius injuries, and plantar fasciitis compared with hypothesized volume‐related injuries; and (2) a running schedule focusing on running volume (S‐V) would increase the risk of sustaining patellofemoral pain syndrome, iliotibial band syndrome, and patellar tendinopathy compared with hypothesized intensity‐related injuries. METHODS: In this randomized clinical trial and etiology study, healthy recreational runners were included in a 24‐week follow‐up, divided into 8‐week preconditioning and 16‐week specific‐focus training periods. Participants were randomized to 1 of 2 running schedules: S‐I or S‐V. The S‐I group progressed the amount of high‐intensity running (88% maximal oxygen consumption [VO2max] or greater) each week, and the S‐V group progressed total weekly running volume. A global positioning system watch or smartphone collected data on running. Running‐related injuries were diagnosed based on a clinical examination. Estimates were reported as risk difference and 95% confidence interval (CI). RESULTS: Of 447 runners, a total of 80 sustained an injury (S‐I, n = 36; S‐V, n = 44). Risk differences (95% CIs) of intensity injuries in the S‐I group were ‐ 0.8% (‐5.0%, 3.4%) at 2 weeks, ‐0.8% (‐6.7%, 5.1%) at 4 weeks, ‐2.0% (‐9.2%, 5.2%) at 8 weeks, and ‐5.1% (‐16.5%, 6.3%) at 16 weeks. Risk differences (95% CIs) of volume injuries in the S‐V group were ‐0.9% (‐5.0%, 3.2%) at 2 weeks, ‐2.0% (‐7.5%, 3.5%) at 4 weeks, ‐3.2% (‐9.1%, 2.7%) at 8 weeks, and ‐3.4% (‐13.2%, 6.2%) at 16 weeks. CONCLUSION: No difference in risk of hypothesized intensity‐ and volume‐specific runningrelated injuries exists between the 2 running schedules focused on progression in either running intensity or volume. LEVEL OF EVIDENCE: Etiology, level 1b.