Except for previous history of injuries, no evidence currently exists to indicate why we get injured. However anecdotally, we can assume that injuries occur when we exceed the body’s capacity to adapt to stress – this tipping is likely to vary greatly amongst individuals.
There are many factors to consider when monitoring our training load and how quickly our body is recovering from these sessions. As technology and wearables continue to develop and improve, we now have more information than ever to monitor training stress and recoverability.
For this article, I will discuss running specifically however principles can be applied to a variety of different sports.
From a training perspective, areas to monitor might include:
Time: total time spent running per session and per week
Distance: total distance per session and per week
Heart rate: maximum heart rate and average heart rate per session, this can further be categorised into heart rate zones. Heart rate can be a useful training stressor to keep an eye on to ensure a clear distinction between easy sessions are hard sessions. This can be particularly important to look into when you are struggling to push hard during the hard sessions or if your easy runs are not feeling very easy. It is common to see endurance athletes spending most of training volume in the middle zone, leading to under recovery and inability to push hard for the harder sessions.
Intensity or rating of perceived exertion: how hard did you find that session on a scale of 0-10 (or using the borg rating scale from 6-20). This is another key indicator to tune into how you are actually feeling during your sessions – are your easy runs feeling hard? If so, it might be worth considering other factors that are likely to influence this such as in session heart rate, heart rate variability, fatigue levels and sleep.
Running surfaces/hills/stairs: they key here is to introduce new things gradually – sudden changes without allowing your body to adapt to changes may result in injuries. Road running compared to trail running are two different sports and will load areas of the body differently. Hills and stairs running is a great way to improve running power and efficiency, however they are very taxing on the posterior chain (hamstrings and calves).
Shoes: the average lifespan of running shoes is about 600km, depending on the body weight of the runner and the durability of the foam in the shoe.
Menstrual cycle: there is increasing evidence to demonstrate changes in hormones throughout a naturally occurring menstrual cycle should be used to guide training intensity and recoverability
From a recovery perspective, areas to monitor might include:
Resting heart rate: best measured at night during sleep for consistency
Heart rate variability: the time difference between each heartbeat. This is a key indicator of training adaptation and overall health
Respiratory rate: how many breaths per minute. Deviation from baseline could indicate a variety of physiological changes
Sleep: how many hours you slept and the quality of that sleep
General energy levels: often measured upon waking, do you feel alert and energetic or waking feeling fatigued and sore
Acute to chronic workload ratios: conflicting evidence exists regarding acute to chronic workload ratios. This looks at the workload ration over the last week of training, compared to the last 4 weeks of training. It factors in volume and intensity of sessions and can be a helpful guide however it is important to remember that different individuals will manage different peaks in training. This tool also fails to consider variances amongst novice runners and experienced runners.
To summarise, there is a lot of data out there that we can dissect and monitor in regard to training load. It is not perfect and unfortunately in some cases, we can still end up with injuries. In saying that, it can be used as a helpful guide to help with monitoring training load. This is a very difficult area to research and study due to the many variables that will influence results, which is why anecdotal evidence can be useful. The other thing to consider is that a lot of wearables have significant inaccuracies, another reason to use the data as a guide but why it is also important to ask yourself how you are feeling.
Our physiotherapists will carry out a thorough assessment to determine your current capacity and develop appropriate training programs to assist you with your injury and/or performance goals.