Load Management

Runners are well aware that training load increases have to be gradual, otherwise they are at risk of injury. To become a faster runner, the load must be increased in order to encourage adaptation, however not be so high that the tissue becomes overloaded resulting in an injury. Runners clearly struggle to find this sweet spot – research indicates that somewhere between 60% and 80% of runners are injured every year, with 80% of runners’ injuries due to overuse. Often when runners begin to see progress, they become highly motivated to train, and therefore begin to run faster and/or further, however frequently do not want to pull back when the warning signs of tissue fatigue and overload are evident.

Provided the training build-up is gradual (and research continues to indicate the importance of the magical 10% increments at a time), the body will absorb the load. However, if the training load is too excessive, then injuries will present. Recognising when tissue tolerance has been surpassed is challenging, as the cause is usually due to numerous training load factors. Tissue tolerance is impacted by the balance between training load and tissue load capacity.

Training load consists of:

  • Volume – total duration/distance
  • Intensity – how hard are the sessions
  • Frequency – how often is the runner training
  • Type – what is the type of training
  • External load factors – eg. work stress, etc
  • Recovery – the amount of rest between sessions

In contrast, the tissue load capacity is dependent on the following:

  • Local tissue tolerance – eg. specific strength of the Achilles tendon to tolerate the load
  • Entire kinetic chain tissue tolerance – eg. the strength of the gluteal muscles to offset the load of the Achilles/calf
  • Diet, age, BMI, medication, metabolic factors, hormonal changes, etc
  • Brain and central nervous system perception to the ‘injured’ site
  • Psychosocial factors – stress, fear of injury, beliefs of pain and injuries, motivation

If the runner suddenly increases the training volume by more than 10% or adds an additional speed session without the ability for the tissue load capacity to absorb and recover from the increased load, then the risk of injury will be significantly higher. Once injuries arise, the current load needs to be decreased, as the tissue load capacity has clearly been surpassed. This doesn’t mean the runner has to completely stop running, but should reduce training load to below the tissue’s capacity.

If the early warning signs of injuries are recognised and paid attention to, then a small reduction in load should settle the overload. However, if the runner continues to run and maintain the current level of training, or, even worse, continues to build load, the tissue will become further irritated. This will result in a longer tissue repair time, more extensive physiotherapy and strengthening, and a greater increase in tissue sensitivity.

Dave Halpin is an Accredited Exercise Physiologist with a special interest in running performance. Together with Michelle Harrison (nee Hynd)  (CityWest) he conducts Running Assessments which include video gait analysis, musculoskeletal assessments and advice on exercises, running drills and training programs.