Defining Training Stress
When most people think of stress, they think about the mind. But managing training or physical stress is essential for all types of athletes. Managing the load and the amount of exercise performed on the body is especially true if you're active in more than one sport or play at a high level.
So what exactly is training stress? Training stress considers the duration and intensity of physical work. Athletes and coaches can use training stress to estimate the overall physical load delivered in a single training session or training block. Why is monitoring this important? When you use a part of the body over and over again, it adds up. This stimulus will (ideally) increase that body's ability to move further and lift heavier. Our body can progress successfully without injury when it's prepared to do so through proper training (5).
Tendon Stress
Structures of the body can even break down with too much stress too fast! One structure that encounters a lot of pressure is tendons. Tendons are thick, band-like connective tissue and bind muscle to bone throughout the body. Tendons absorb and transfer energy and allow us to move, like when we're running and jumping. When we place stress on tendons, like other parts of the body, the tissue breaks down and regenerates with proper recovery. The body's ability to restore, or redevelop, is how we can create a more extensive endurance and strength capacity through training. At any given time, our tissues have a load limit or tolerance. The goal of training is to train slightly over the limit and provide adequate recovery, so the limit increases for next time. This process is disrupted if too much stress is placed on body structures too fast without proper healing. Lack of recovery can lead to pain, swelling, and even long-term injuries. Without monitoring our activity volume, we are likely to encounter an injury (5,1). By managing training stress, we can work with our bodies instead of against it to become better athletes!
Nutrition Tip: Taking collagen peptides in the 30 to 60 minutes prior to training may make tendons, ligaments, and joints healthier, stronger, and more resilient.
Turn up the volume (or don’t!)
You've likely heard the term "volume" regarding resistance training or running. Volume is the amount of work done during a period, like during a training session or week (5). On a basic level, you can increase volume by adding sets, reps, or weight to your lift or miles, elevation gain, and intensity during your run or bike. Increasing one or more of these variables will cause progressive overload. Progressive overload ultimately means doing more than last time. After properly progressing, the nervous system can handle new stress levels, meaning new strength and endurance abilities (5). Fatigue can be broken down into fatigue or stress into local, one body part, and systematic, general fatigue (1). When fatigue and recovery are overlooked, it can manifest differently but generally results in decreased performance or injuries (6). Weekly volume should only gradually increase to avoid damage and improve physical ability. Volume is determined for both resistance training and endurance activities using calculations. It is essential to monitor your training volume to ensure you're progressing at a rate that will encourage improvements in abilities while reducing your risk for injury.
Sets x Reps x Load
One way to define a resistance training session's volume is by multiplying Sets x Reps x Load. Say you're working on increasing the amount you can deadlift. You performed three sets of 10 repetitions at 100 lbs during one lift. To calculate the training load for this movement, you'd multiply 3 (Sets) x 10 (Reps) x 100 (Load). The training load for your deadlift that day is equal to 3,000. This calculation is excellent when you compare an exercise or movement to itself. One weakness of this approach is that not every lift is equal. Some exercises are more manageable to jump in weight than others because of their relative strength. Another general rule of thumb is adding 5-10lbs for lower body movements and 2.5-5lbs for upper body movements each week (5).
The 10 Percent Rule
Athletes and coaches can use the 10 percent rule (10PR) to compare lifts or mileage on a week-to-week basis. The 10PR states that an athlete should not increase volume by more than 10 percent over your previous week of training (8). As mentioned before, this goal is to improve abilities while reducing injury risk. Regulating volume is especially true for runners and cyclists because most of their injuries are due to increasing volume too fast, known as overuse (6, 7). Based on the deadlift example, this would mean that this athlete would gauge their next week's training of their previous volume of 3,000. Based on the 10PR, this athlete can increase up to a new volume of 3,300, translated to 3x10 at 110lbs for the next week. For endurance activities, this rule works like this. If a runner ran a total of 20 miles last week, the 10PR recommends an athlete increase next week's volume by no more than 2 miles. Although the 10 percent rule is a good tool, there are ways to monitor volume more specifically.
The Acute to Chronic Training Ratio
The 10PR is a guide to monitoring volume but struggles to monitor mileage accumulated over time and the intensity of a training session. The trick is understanding what is too much versus too little. Compared to the 10PR, a more precise approach is called the Acute to Chronic Training Ratio (ACTR). This calculation helps an athlete or coach identify the line between too little and too much activity by creating a ratio comparing your mileage over the last week (acute) to your monthly average (chronic). The ACTR suggests that if an athlete's short-term training (acute or one week) is near or slightly above their long-term (chronic, four-plus weeks of training), an athlete will enhance their performance and be less likely to meet injuries (2, 3, 4).
Say you ran 20 miles, 10 miles, 20 miles, and 30 miles in the past four weeks, respectably. First, take the last month's average by adding the weekly totals and dividing by 4; you get 20 miles. Next, you divide previous week's mileage (30) by the monthly average (20), you end up with 1.5. Research shows when the ratio climbs above 1.5, there is an increased injury risk. If an athlete chose to use the 10PR to increase mileage each week for a month, this would lead to a ratio of 1.15, which is considered safe in terms of injury risk (2, 3, 4, 10, 13). The ACTR dials into an athlete's mileage progression over several months, whereas the general 10PR focuses on just the previous training week. This narrow lens can overlook fluctuations in training that may have occurred a few weeks back.
Measuring Intensity
An athlete can get even more comprehensive using the ACTR by considering intensity, not just miles. Training intensity is how challenging the training session was. Higher intensity workouts, when used appropriately, can help the body be more resilient to more difficult races and terrain. Higher intensity exercises place more significant stress on the body than easy sessions. Calculating your training load ratio can help monitor this delicate balance. For a single training session, you can rate the intensity on a scale from 1 (no effort) to 10 (maximum effort). Next, multiply your rating by the workout duration in minutes to get a more specific measure of training load. If your last run was 60 minutes long with an intensity rating of 5, the training load score for that session would be 300. By adding up each session's load during a week, you can calculate a more specific ratio using intensity instead of miles. Like we did earlier using mileage, you would look back at the past four weeks' training loads and take the average. For the last four weeks, your training loads were 1,000, 1,200, 1,200, and 1,000. Your ratio is 1,000 (last week's training load) divided by 1,100 (average training load over the past month), equaling 0.9. This value is below the 1.5 injury risk threshold (2, 3, 4, 13).
When monitoring your training stress, whether resistance training or endurance activities, it is essential to pick an approach based on your needs and stick to it for consistency. Some smartwatches automatically calculate a training score for workouts. Using this score in place of calculating your own is another option. Tracking the changes among your ratios is also necessary. Say your training volume/intensity scores have been lower than usual for two weeks because you've been on vacation; there still needs to be a gradual increase in your ratio as you get back to your "normal" training volumes. A significant jump in volume can impact your injury risk if inadequate training.
Deloading or tapering is the final consideration when managing your training stress. If you increase your volume for months on end, you’ll eventually face decreased performance, mental stamina and motivation, and overuse injuries (12). Never-ending increases in training may not encourage a healthy long-term relationship with movement and could make the journey less enjoyable. Insufficient or nonexistent recovery promotes long-term aches and pains that’ll take longer to heal than if you prioritized regular rest. A deload or taper is a planned period of decreased volume and recovery. Athletes that commit to tapering can expect to see increases in power and strength up to 20 percent, a higher muscle damage resistance after future workouts, and even enhanced sleep (9, 12). A deload period may include a drop of volume by 30 to 50 percent and is routinely scheduled after a few weeks of rigorous training to give the mind and body a break. Although reducing volume during a taper, intensity shouldn’t drop more than 30 percent during a deload (12).
The amount an athlete should deload depends on the demands of their sport and their experience training. Deloading every 8 to 10 weeks for new athletes is sufficient. Athletes with 1 to 3 years of experience should consider a deload every 6 to 8 weeks. Athletes with training experience more significant than three years should plan a deload from once a month to every six weeks. All athletes should plan a taper week and stick to it; over time, you can begin to gauge how often you need to deload based on how your body feels and how your motivation fluctuates (5, 12).
Mental Fatigue
Being an athlete also comes with psychological stress. You likely have a full-time job or are going to school, which adds extra weight to the equation. Having a stressful job or balancing school and your sport can also make you more likely to get injured and even slow down your recovery. Performance excellence depends on creating a balance that works for the athlete and doesn't neglect other areas of wellness like financial, social, and psychological (12). Many companies and schools offer discounted or even free mental health resources for their people. When you're having a particularly stressful week, this is the perfect time to deload volume. Using movement to get your mind stressed is valuable during these times. Active recovery, including light yoga, walking, or other leisure activities, can help your mind and prevent injuries. Perfectionism, pressure to perform, and sponsorships can almost make your sport feel like work. Developing a self-care routine, asking about your resources, and speaking to professionals are ways to navigate your mental wellness alongside developing as an athlete.
Take-Aways
There are many approaches to managing training stress; each system has its pitfalls and considerations. When it comes down to it, tracking your volume any way is more valuable than not. It's up to you to decide which method to use; there's no one size fits all. The biggest takeaway from this information is to consider how much stress you're routinely placing on the body, monitor it, and keep an eye out for patterns. Using whichever method you choose, being self-aware will reduce your risk for injury and keep you doing what you love for longer.
References
- Goethel, M. F., Gonçalves, M., Brietzke, C., Cardozo, A. C., Vilas-Boas, J. P., & Ervilha, U. F. (2020). A global view on how local muscular fatigue affects human performance. Proceedings of the National Academy of Sciences, 117(33), 19866-19872.
- Gabbett, T. J., Hulin, B. T., Blanch, P., & Whiteley, R. (2016). High training workloads alone do not cause sports injuries: how you get there is the real issue.
- Gabbett, T. J., & Whiteley, R. (2017). Two training-load paradoxes: can we work harder and smarter, can physical preparation and medical be teammates?. International journal of sports physiology and performance, 12(s2), S2-50.
- Griffin, A., Kenny, I. C., Comyns, T. M., & Lyons, M. (2020). The association between the acute: chronic workload ratio and injury and its application in team sports: a systematic review. Sports Medicine, 50(3), 561-580.
- Haff, G. G., & Triplett, N. T. (Eds.). (2015). Essentials of strength training and conditioning 4th edition. Human kinetics.
- Hreljac, A. (2004). Impact and overuse injuries in runners. Medicine and science in sports and exercise, 36(5), 845-849.
- James, S. L., Bates, B. T., & Osternig, L. R. (1978). Injuries to runners. The American journal of sports medicine, 6(2), 40-50.
- Johnston CA, Taunton JE, Lloyd-Smith DR, McKenzie DC. Preventing running injuries. practical approach for family doctors. Can Fam Physician 49: 1101–1109, 2003.
- Mangine, G. T., Hoffman, J. R., Gonzalez, A. M., Townsend, J. R., Wells, A. J., Jajtner, A. R., ... & Stout, J. R. (2015). The effect of training volume and intensity on improvements in muscular strength and size in resistance‐trained men. Physiological reports, 3(8), e12472.
- Wang, C., Vargas, J. T., Stokes, T., Steele, R., & Shrier, I. (2020). Analyzing activity and injury: lessons learned from the acute: chronic workload ratio. Sports Medicine, 50(7), 1243-1254.
- Wiese‐Bjornstal, D. M. (2010). Psychology and socioculture affect injury risk, response, and recovery in high‐intensity athletes: a consensus statement. Scandinavian journal of medicine & science in sports, 20, 103-111.
- Wilson, J. M., & Wilson, G. J. (2008). A practical approach to the taper. Strength & Conditioning Journal, 30(2), 10-17.
- Zouhal, H., Boullosa, D., Ramirez-Campillo, R., Ali, A., & Granacher, U. (2021). Acute: Chronic Workload Ratio: Is There Scientific Evidence?. Frontiers in Physiology, 12.
