5A 109 INCREASING WORKLOAD RELATES TO INJURY RISK IN RUNNING Table 1. Baseline characteristics of the runners. Male Female Total Number 16 7 23 Age (years; mean ± SD ) 22.5 ± 6.3 21.4 ± 4.4 22.2 ± 5.7 Height (cm; mean ± SD) 185 ± 5 172 ± 7 181 ± 8 Body weight (kg; mean ± SD) 68.6 ± 6.0 58.3 ± 4.0 65.4 ± 7.2 Percentage body fat* (%; mean ± SD) 8.5 ± 2.3 17.6 ± 4.2 11.3 ± 5.2 VO2max**(ml/kg/min; mean ± SD) 66.7 ± 5.9 62.7 ± 7.4 65.5 ± 6.5 SD = Standard Deviation; cm = centimetre; kg = kilogram; ml = millilitre; min = minutes; VO2max = Maximal measured Oxygen Uptake *The percentage body fat was estimated using the Tanita BC 418. **The VO2max was measured with a maximal incremental treadmill test including breath-by-breath gas analysis using the Cortex Metalyzer 3 B. 2.2. Definition of injury An injury was defined as any musculoskeletal problem of the lower extremity or back that led to an inability to execute training or competition as planned for at least one week [25]. Only injuries sustained as a result of training or competition were considered. Recovery from an injury was defined as the ability to complete the normal training schedule. At the start of the study, the runners filled out a validated questionnaire on injury history based on Fuller et al. [26]. During the study period of 24 months, the runners kept a daily log on sustained injuries. The coach added information about the observed injuries to this log. 2.3. Quantifying workloads The coach developed a training and competition schedule for each runner and recorded the ability of the individual runner to execute the planned schedule. Each individual runner filled out their daily training and competition schedule for duration and intensity of all training sessions and running competition events. The training sessions consisted of various types of training, for example endurance training, technique training, and strength training. The duration of the training and competition sessions was reported in minutes. In addition, the intensity was determined by the rating of perceived exertion per session (sRPE), which was reported by the runners approximately 30 minutes after each session on the Borg Scale ranging from 6 to 20 [27]. The workload of each training session and competition event was calculated by multiplying the sRPE scores with the duration and was expressed in arbitrary units (AU). 2.4. Data analysis Data of one runner was removed from the data set for not adequately recording duration and intensity. The remaining data on workload were divided into weekly blocks from Monday to Sunday. The weekly blocks represent the acute workload. The chronic
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