Comparison of weekly training load and acute:chronic workload ratio methods to estimate change in training load in running.

CONTEXT: Before examining the impact of training load on injury risk in runners, it is important to gain insight in the differences between methods that are used to measure change in training load. OBJECTIVE: To investigate differences between four methods to calculate change in training load: (1) weekly training load; (2) acute:chronic workload ratio (ACWR), coupled rolling average (RA); (3) ACWR, uncoupled RA; (4) ACWR, exponentially weighted moving averages (EWMA). DESIGN: Descriptive epidemiology study. SETTING: This study is part of a randomized-controlled trial on running injury prevention among recreational runners. Runners received a baseline questionnaire and a request to share GPS training data. PARTICIPANTS: Runners who registered for running events (distances 10-42.195 kilometers) in the Netherlands. MAIN OUTCOME MEASURES: Primary outcome measure was the predefined significant increase in training load (weekly training loads ≥30% progression and ACWRs ≥1.5), based on training distance. Proportional Venn diagrams visualized the differences between the methods. RESULTS: 430 participants (73.3% men; age 44.3 years) shared their GPS training data with in total 22,839 training sessions. For the weekly training load, coupled RA, uncoupled RA, and EWMA method, respectively 33.4% (95% CI 32.8-34.0), 16.2% (95% CI 15.7-16.6), 25.8% (95% CI 25.3-26.4), and 18.9% (95% CI 18.4-19.4) of the training sessions were classified as significant increase in training load. Of the training sessions with significant increase in training load, 43.0% expressed in the weekly training load method showed a difference with the coupled RA and EWMA method. Training sessions with significant increase in training load based on the coupled RA method showed 100% overlap with the uncoupled RA and EWMA method. CONCLUSIONS: The difference in change in training load measured by weekly training load and ACWR methods was high. To validate an appropriate measure of change in training load in runners, future research on the association between training loads and RRI risk is needed.

Epidemiology of insertional and midportion Achilles tendinopathy in runners: A prospective cohort study.

BACKGROUND: Achilles tendinopathy (AT) is a common problem among runners. There is only limited evidence for risk factors for AT, and most studies have not defined the AT subcategories. No study has compared the incidence and risk factors between insertional AT and midportion AT, though they are considered distinct. This study aimed to assess incidence and risk factors of AT based on data from a large prospective cohort. The secondary aim was to explore differences in risk factors between insertional and midportion AT. METHODS: Participants were recruited from among registered runners at registration for running events. Questionnaires were completed at baseline, 1 month before the event, 1 week before the event, and 1 month after the event. Information concerning demographics, training load, registered events, and running-related injuries were collected at baseline. The follow-up questionnaires collected information about new injuries. A pain map was used to diagnose midportion and insertional AT. The primary outcome was the incidence of AT. Multivariable logistic regression analysis was applied to identify risk factors for the onset. RESULTS: We included 3379 participants with a mean follow-up of 20.4 weeks. The incidence of AT was 4.2%. The proportion of insertional AT was 27.7% and of midportion AT was 63.8%; the remaining proportion was a combined type of insertional and midportion AT. Men had a significantly higher incidence (5%, 95% confidence interval (95%CI): 4.1%-6.0%) than women (2.8%, 95%CI: 2.0%-3.8%). AT in the past 12 months was the most predominant risk factor for new-onset AT (odds ratio (OR) = 6.47, 95%CI: 4.27 -9.81). This was similar for both subcategories of AT (insertional: OR = 5.45, 95%CI: 2.51-11.81; midportion: OR = 6.96, 95%CI: 4.24-11.40). Participants registering for an event with a distance of 10/10.55 km were less likely to develop a new-onset AT (OR = 0.59, 95%CI: 0.36-0.97) or midportion AT (OR = 0.47, 95%CI: 0.23 -0.93). Higher age had a significant negative association with insertional AT (OR = 0.97, 95%CI: 0.94-1.00). CONCLUSION: The incidence of new-onset AT among recreational runners was 4.2%. The proportion of insertional and midportion AT was 27.7% and 63.8%, respectively. AT in the past 12 months was the predominant risk factor for the onset of AT. Risk factors varied between insertional and midportion AT, but we could not identify clinically relevant differences between the 2 subtypes.

Feasibility and usability of GPS data in exploring associations between training load and running-related knee injuries in recreational runners.

BACKGROUND: The purpose of the present study was to explore the feasibility of collecting GPS data and the usability of GPS data to evaluate associations between the training load and onset of running-related knee injuries (RRKIs). METHODS: Participants of the INSPIRE-trial, a randomized-controlled trial on running injury prevention, were asked to participate in this study. At baseline, demographic variables were collected. Follow-up questionnaires assessed information on RRKIs. Participants with a new reported RRKI and uninjured participants were sent a GPS export request. Weekly GPS-based training distances were used to calculate Acute:Chronic Workload Ratios (ACWRs). RESULTS: A total of 240 participants (62.7%) tracked their running training sessions with the use of a GPS-enabled device or platform and were willing to share their GPS data. From the participants (N = 144) who received a GPS export request, 50.0% successfully shared their data. The majority (69.4%) of the shared GPS data were usable for analyses (N = 50). GPS data were used to present weekly ACWRs of participants with and without an RRKI eight weeks prior to RRKI onset or running event. CONCLUSIONS: It seems feasible to collect GPS data from GPS-enabled devices and platforms used by recreational runners. The results indicate that GPS data is usable to calculate weekly ACWRs to evaluate associations between training load and onset of RRKIs in recreational runners. Therefore, GPS-based ACWR measures can be used for future studies to evaluate associations between training load and onset of RRIs.

Educational online prevention programme (the SPRINT study) has no effect on the number of running-related injuries in recreational runners: a randomised-controlled trial.

OBJECTIVES: The aim of this study was to examine the effectiveness of an enhanced online injury prevention programme on the number of running-related injuries (RRIs) in recreational runners. METHODS: We conducted a randomised-controlled trial in runners who registered for running events (distances: 10-42.195 km) in the Netherlands. Adult runners who provided informed consent were randomised into the intervention or control group. Participants in the intervention group received access to the online prevention programme, which included items to prevent RRIs. Participants in the control group followed their regular preparation for the running event. The primary outcome measure was the number of new RRIs from baseline to 1 month after the running event. To determine differences between injury proportions, univariate and multivariate logistic regression analyses were performed. RESULTS: This study included 4050 recreational runners (63.5% males; mean (SD) age: 42.3 (12.1) years) for analyses. During follow-up, 35.5% (95% CI: 33.5 to 37.6) of the participants in the intervention group sustained a new RRI compared with 35.4% (95% CI: 33.3 to 37.5) of the participants in the control group, with no between-group difference (OR: 1.03; 95% CI: 0.90 to 1.17). There was a positive association between the number of items followed in the injury prevention programme and the number of RRIs (OR: 1.05; 95% CI: 1.00 to 1.11). CONCLUSION: The enhanced online injury prevention programme had no effect on the number of RRIs in recreational runners, and being compliant with the programme paradoxically was associated with a slightly higher injury rate. Future studies should focus on individual targeted prevention with emphasis on the timing and application of preventive measures. TRIAL REGISTRATION NUMBER: NL7694.

Consequences and Prognosis of Running-Related Knee Injuries Among Recreational Runners.

OBJECTIVE: To investigate the consequences and prognostic factors of running-related knee injuries (RRKIs) among recreational runners. DESIGN: Prospective cohort study. SETTING: This study is part of a randomized-controlled trial (RCT) on running injury prevention among recreational runners. At baseline during registration for a running event (5-42 km), demographic and training variables were collected. Participants who reported a new RRKI during follow-up were sent a knee-specific questionnaire at 16 months (range 11.7-18.6) after baseline. PARTICIPANTS: One hundred thirty-eight runners who reported a new RRKI during the RCT on injury prevention responded to the knee-specific questionnaire. ASSESSMENT OF RISK FACTORS: To determine the association between potential prognostic factors and time to recovery of an RRKI, a Cox regression analysis was performed. MAIN OUTCOME MEASURES: Time to recovery and prognostic factors of RRKIs. RESULTS: At 16 months after registration, 71.0% of the participants reported full recovery, with a median time to recovery of 8.0 weeks. Most participants reported iliotibial band syndrome (23.2%) or osteoarthritis (OA)/degenerative meniscopathy (23.2%) as cause of their injury. Male sex was associated with a shorter time to recovery [hazard ratio (HR) 1.84; 95% confidence interval (CI), 1.14-2.97], while suffering knee OA was associated with a longer time to recovery (HR 0.17; 95% CI, 0.06-0.46). CONCLUSIONS: Nonrecovered participants adjusted running speed more often and had knee imaging more often than recovered participants. At follow-up, one-third of the participants were not recovered. This emphasizes the need for injury prevention programs for runners. More knowledge on the role of running in knee OA seems important, given the high number of participants with knee OA symptoms.

Running behavior and symptoms of respiratory tract infection during the COVID-19 pandemic: A large prospective Dutch cohort study.

OBJECTIVES: To explore changes in running behavior due to the Coronavirus Disease 2019 (COVID-19) pandemic, assess presence of symptoms suggestive for COVID-19 and identify whether there is an association between running behavior and COVID-19. DESIGN: Prospective cohort study. METHODS: For this study we used a cohort of runners participating in an ongoing randomized controlled trial on running injury prevention among recreational runners. At baseline, demographic and training variables were collected. Seven weeks after starting the lockdown, information on running behavior (interval training, training with partner and physical distancing during training) and running habits (training frequency, duration, distance and speed) were obtained. Furthermore, healthcare utilization and symptoms suggestive for COVID-19 were assessed. To determine the association between running and symptoms suggestive for COVID-19, univariate and multivariate logistic regression analyses were performed. RESULTS: Of the 2586 included participants, 2427 (93.9%) participants continued running during lockdown with no significant changes in mean weekly training variables. A total of 253 participants (9.8%) experienced symptoms suggestive for COVID-19 and 10 participants tested positive for COVID-19. Two participants were admitted to hospital due to COVID-19 with both one day of admission. Running behavior and running habits were not associated with the onset of symptoms suggestive for COVID-19. CONCLUSIONS: The large majority of runners in the Netherlands did not change their running habits during lockdown. No association between running behavior or running habits and onset of symptoms suggestive for COVID-19 was identified. This implicates that running outdoor during lockdown does not negatively affect health of runners.