Modern athletic preparation is organised around a measurement called training load. It exists because the body responds to accumulated stress rather than to individual sessions, and that accumulation needs a number.
External and internal load are different things
External load describes what an athlete physically did, such as distance covered, accelerations performed or weight lifted. It is objective and recorded by equipment.
Internal load describes the physiological cost of that work, captured through heart rate or an athlete's own rating of exertion. The same session produces different internal loads in different people.
Both are needed, because the relationship between them reveals condition. An unchanged external load producing a rising internal cost suggests fatigue or illness.
Simple methods remain widely used
Multiplying session duration by a rating of perceived exertion produces a single figure requiring no equipment. The method is used from professional to amateur settings.
Its simplicity is a strength, since it can be applied consistently across every session including those where tracking devices are impractical.
The rating is collected shortly after a session and before discussion with teammates, because reported exertion is easily influenced by others' answers.
The pattern matters more than the total
Accumulated load over recent weeks represents preparedness, while load in the current week represents immediate stress. Comparing the two describes how unusual the present demand is.
Sharp increases relative to accustomed levels have been associated with elevated injury risk, particularly when preceded by a period of low activity.
The practical guidance is therefore about the rate of change rather than the absolute amount. Well-prepared athletes tolerate high loads that would injure an unprepared one.
Limitations of the approach
Load measures describe groups better than individuals, and no threshold reliably predicts injury for a specific athlete. They inform decisions rather than making them.
Many contributing factors sit outside the measure entirely, including sleep, stress, nutrition and previous injury. A complete picture requires more than the load figure.
Staff therefore combine load data with wellness questionnaires and direct observation. Disagreement between the sources is itself informative.
How the information is actually used
Load monitoring is used mainly to plan forward, distributing demand across a week so that hard sessions are followed by recovery. It is a planning tool rather than an alarm.
It also supports return from injury, where exposure must be increased gradually and documented. The record shows whether progression matched the plan.
Interpretation requires qualified staff who understand the sport and the individual. The numbers describe stress but do not decide what an athlete should do next.
