Critical concepts in reducing running-related injuries. Part 1

Running workload and bodyweight

Introduction

In the previous post, we explored running concepts and foot strike patterns. Two key conclusions emerged:

1. There is unlikely to be a single optimal foot strike pattern for all runners.

   
   

2. Understanding how the body absorbs and generates forces during running allows us to prepare sensibly, maximise enjoyment, and reduce injury risk.

   
   

Running injuries typically develop gradually from cumulative loading, eventually reaching a tipping point that causes pain and ultimately restricts or stops activity. Beginners, competitive distance runners, and those training at high speeds appear at greatest risk, while most recreational runners fall in a lower-risk middle ground (1) (Fig. 1).

Fig 1.

Beyond running level, other factors that reduce the body’s ability to adapt to high-impact demands must also be considered (Fig. 2).

Fig 2.

If you recognise yourself in this higher-risk profile, understanding the modifiable factors discussed below can be particularly valuable.

Four critical modifiable risk factors

Four key areas that runners can actively influence are:

• Running workload

• Body weight

• Muscle preparation and maintenance

• Running form

  
  

For those who are risk-averse, addressing all four is wise. Today’s post focuses on running workload and body weight, which I consider foundational, especially for high-risk beginners and irregular runners.

Running workload

Bones, tendons, joints, and muscles adapt more slowly than runners can increase distance or speed. It is therefore unsurprising that training error remains one of the strongest risk factors for running-related injury (2). Many freely available online training plans lack strong evidence and offer conflicting advice, which can confuse runners or create false confidence.

Educating yourself about workload, the combination of volume (distance) and intensity (speed/effort) in a session, can significantly reduce training error and injury risk. For runners with goals involving large increases in distance or speed, planning frequency and progression (a “running cycle”) becomes essential.

It remains unclear whether rapid increases in volume or intensity pose the greater risk. One study of experienced recreational runners found no difference in absolute injury risk between groups increasing either volume or intensity, but modest volume increases (6 km over 16 weeks) and sudden intensity changes both elevated risk (3) (Fig. 3).

Many popular plans exceed these modest changes and are often followed by beginners, a concerning combination.

Fig 3.

Regardless of your goals, managing volume and intensity while allowing adequate recovery is likely to lower injury risk. Low-risk runners can usually avoid sudden changes and progress gradually. The commonly cited 10% weekly increase rule is a reasonable starting point, but more conservative progression is prudent for those at higher risk (4).

For higher-risk or risk-averse runners, the following principles are recommended:

• Use longer training cycles with modest progression.

  
  

• Limit volume increases within a cycle to a maximum of 30%, followed by 1–2 weeks of 10% tapering before starting a new cycle (Fig. 4).

Fig 4.

Monitoring Intensity

Intensity can be monitored simply by recording time and perceived effort (0 = easy, 10 = extremely hard) after each run and keeping effort consistent within a cycle (i.e. 5–7/10 for each run). For greater precision, track average heart rate. For beginners, aim for 50–70% of maximum heart rate (roughly 90–126 bpm for a 40-year-old, calculated as 220 minus age), which promotes sustainable aerobic efforts without overexertion (5, 6). Fitter runners can sustain 70–85% during longer sessions. Maintaining consistent average heart rate within cycles helps detect unintended jumps in effort and supports safe progression.

The table below is a guide to planning your training cycle. If you are unsure about your starting level, stay conservative and treat yourself as a high-risk beginner or irregular runner. For greater clarity, I have provided a detailed Couch-to-5k schedule for high-risk/irregular runners based on these principles at the end of this post as an example.

Before going straight to the example, however, please take a moment to consider the next critical factor in reducing running related injuries: bodyweight.

Bodyweight

Running is an effective way to burn calories. A 90 kg person running at 12 km/h for 1 hour (completing 12 km) expends approximately 1,000 kcal, compared with 270 kcal walking 4 km in the same time. However, many heavier individuals struggle to sustain an hour of running, and the body often compensates with increased hunger or subsequent inactivity, resulting in little net energy deficit or weight loss.

Excess body fat increases risk of overuse injuries to tendons, bones, and joints, largely because higher body weight amplifies impact forces and muscle activation demands, contributing to cumulative microtrauma (7, 8).

Normal body fat ranges vary by age and sex, DEXA scans provide precise measurement. For a rough estimate, BMI can be used (though less accurate for muscular individuals). There is no “ideal” BMI to start running, but a higher BMI flag’s an increased risk. You can check your BMI here.

Sustainable Fat Loss Strategies

Sustainable fat loss requires creating a situation where the body mobilises stored fat for energy. Insulin, the primary regulator of fat storage, rises sharply after consumption of excess energy-dense, refined carbohydrates (sugars and starches) (9, 10). Reducing these while increasing daily physical activity is often effective.

Subtle habit changes, walking instead of driving, taking stairs, adding 12 km of weekly walking (14–16,000 steps) equivalent to an extra 20-25 minutes a day, can accumulate meaningfully. For our 90 kg person example, an extra 12 km walked weekly for a year equates to 38,880 kcal, roughly 5 kg of fat loss when combined with dietary adjustments

Next Steps

In the next post, I will discuss specific exercises and running form modifications to further prepare the body for running’s physical demands.

Example Couch-to-5k Schedule (for high-risk beginners focusing on gradual distance progression, not speed). Aim for at least 48 hours gap between runs.

A small disclaimer, these are guidelines, evidence on optimal progression is variable, so monitor for signs of overload (e.g. persistent soreness). If you’re unsure, consider professional guidance. 

Thanks for reading. Feel free to reach out if you’d like to discuss your running workload or individual circumstances.