How do training and competition workloads relate to injury? This question was recently addressed in several articles published in the British Journal of Sports Medicine.
Workload is the total amount of stress applied over time. When an athlete trains or competes, they are exposed to various workloads. The nature of the workload and characteristics of the athlete (predisposition) together determine an individual's susceptibility for injury during any given training session or competition.
The Predisposed Athlete
Multiple factors may predispose an athlete to injury, such as:
The Susceptible Athlete
Increasing workload (the total amount of stress placed on an individual over time through training and competition) results in both increased fitness and fatigue, and either positive adaptation or injury (negative adaptation). Three factors are commonly manipulated to alter training workloads -- frequency, intensity, and duration. Remember that a key principle of training is individuality -- athletes respond to external loads differently based how characteristics of the external workload interact with their individual biomechanics and physiology (their predisposition).
Athletes who are exposed to sudden or chronically high external stress are susceptible to injury. These kinds of workloads decrease an individuals ability to adapt, and overwhelm their capacity for improvements in modifiable risk factors -- tissue resilience, neuromuscular control, etc. Interestingly, chronically low workloads can also increase risk of injury... not enough stress for adaptation, or the stress does not resemble competition stresses.
Finding the Right Workload
Considering all of the above, how do you find the right workload?
Drew, M., Cook, J., & Finch, C. (2016). Sports-related workload and injury risk: simply knowing the risks will not prevent injuries: narrative review. Br J Sports Med., 50, 1306-1308
Gabett, T. (2016). The training-injury prevention paradox: should athletes be training smarter and harder? Br J Sports Med, 16(50), 273-280 (Full Text)
Windt, J. & Gabbett, T. (2016). The workload-injury aetiology model. Br J Sports Med., Online First. (Great Info-graphic in this link)