In the realm of sports and athletics, the significance of an athlete’s body weight (BW) cannot be overstated. A good example of this is basketball players looking to increase their muscle mass or improve body composition. While both of these scenarios present important goals for the athlete, we must make sure that working toward those goals has a positive outcome for performance. In this article, we explore the concept of the body-weight-to-performance ratio—a metric that offers a nuanced understanding of how weight fluctuations influence athletic performance.
Body Weight’s Crucial Role
Athletes across various disciplines recognize the pivotal role that body weight plays in their respective sports. However, the perspective on body weight is often polarized—seen as detrimental in terms of fat gain or advantageous in terms of muscle gain. Any experienced coach understands how multifactorial weight fluctuations become, especially with college and younger professional athletes. Weight also becomes a touchy subject for athletes, coaches, and administration.
To expand on this issue before exploring the ratio, the discussion of weight in the context of sports is often characterized by its sensitivity, with athletes, coaches, and administration grappling for a delicate balance between optimizing performance and safeguarding the mental well-being of individuals. Athletes face external pressures and expectations related to their physique, particularly in sports that emphasize specific body types. This can give rise to heightened awareness and potential body scrutiny, contributing to a culture where weight becomes an uncomfortable subject.
The pursuit of an optimal body weight—for performance reasons—may inadvertently lead to mental health challenges, such as stress and anxiety, and could even result in the development of eating disorders among athletes. Coaches and administrators play a crucial role in navigating this landscape by fostering an environment that prioritizes both physical and mental health. We must understand this issue before incorporating bodyweight data collection and involve every individual in the department who works with the athlete.
Coaches and administrators play a crucial role in navigating this landscape of ‘optimal body weight’ by fostering an environment that prioritizes both physical and mental health. Share on XTo name just two of the steps that I have taken in the past to prevent these issues:
- Every athlete must give consent to the coach before collecting bodyweight data—addressing this individually and not as a group is important to allow each athlete to be comfortable with their decision.
- Data must be collected individually and privately, with only the athlete and coach allowed to see and analyze the data. No one else must have access to the data unless the athlete gave consent or it is for medical purposes.
In many cases, negative or positive connotations are added to fluctuations that, even when subtle, we tend to classify as one or the other without really knowing their effect on performance. We all understand what is actually good or bad for health, but in this case, I am trying to focus on pure athletic performance and seasonal or subtle weight fluctuations.
Relative Strength Ratios in Question
Traditionally, relative strength ratios have been considered a valid metric for assessing athletic performance, or at least to establish baselines of “strength needs” for athletes (in many cases associating “strength numbers” in the weight room to the ability of athletes to perform plyometrics or athletic actions). This, however, is a flawed perspective—weight room “strength” and an athletic action’s “strength” are not the same. They might complement each other in a way and even be related to the athlete’s overall athletic ability, but they will never depend on one another.
The demands of sports are rooted in speed and power rather than absolute strength. Therefore, it becomes imperative to reevaluate the metrics used to measure performance in these domains. This is not to say that slow strength in the weight room is not an important aspect for health and performance; however, it can’t be “required” or expected for a lot of athletes to hit certain numbers when it comes to weight room strength, especially once we understand that the expression of force is completely different in both scenarios.
So, although these strength ratios I just mentioned might not have much to do with the BW of the athlete, they are ratios that have been used to evaluate performance, and they serve the purpose for an example.
Athletic performance is highly dependent on body weight. It is a good idea to track body weight in coordination with KPIs. Share on XIn this article, I am more interested in understanding in a more insightful way how the fluctuations of athlete’s BW can impact their performance. The BW/performance ratio is a metric designed to provide a more comprehensive understanding of the intricate relationship between an athlete’s weight and their performance. This ratio involves dividing key performance indicators (KPIs) such as countermovement jump height (CMJh), Reactive Strength Index modified (RSImod), etc., by the athlete’s body weight in pounds or kilograms.
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Ex: CMJh÷ BW (kg/lbs)
The first consideration when using this ratio is that, initially, it will not serve the purpose of classifying athletes since we don’t have a pool of data to compare to; instead, it will provide an understanding of how an athlete’s BW changes affect performance at a more detailed level.
Who Is This Useful For?
If you have a pair of force plates, this might not be as useful for you since you can track relative metrics to get the same monitoring concept—although you could still use it to have a broader picture of what is happening with performance by using outcome metrics (take-off speed, RSImod, etc.) instead of raw metrics (peak force, impulse, etc.). If your only access to technology is a contact mat, a Vertec, or even speed gates, this can be a perfect situation to apply the BW-to-performance ratio with your athletes.
Now, let’s discuss five potential scenarios that we can find in real life (using CMJh for the ratio):
1. Increase in Performance and Body Weight:
The chart above shows a positive change in ratio, which indicates a positive change—we can assume here that if the athlete is trying to gain muscle, we are on the right path with our strategy. This can also be useful when an athlete gains weight with no desire behind that increase (this can happen with female athletes, in particular, or certain sports that see weight gain as a negative thing). In this case, this ratio can be used to prove to that athlete and coach that this weight gain is having a positive impact on their performance and is something they can take pride in.
2. Increase in Performance and Decrease in Body Weight:
In this chart, we can also see a positive change in the ratio, which indicates that the athlete’s weight loss isn’t having a negative impact but is actually helping performance. This scenario can be found with athletes looking to improve body composition and needing to monitor that weight loss is being done correctly. It can also be helpful in situations where athletes lose weight unintentionally, and this triggers an alarm with coaches. An athletic trainer tracking changes in this ratio can help the high-performance team and coaches identify whether such weight loss is concerning.
3. Decrease in Performance and Increase in Body Weight:
In the scenario of weight gain and performance loss, the change in ratio will be negative. Although this can be a normal reaction to weight gain—and in some cases, it might be something that coaches and athletes are willing to sacrifice for a greater benefit—in a majority of cases, where the goal is rate of force development and relative force, this will indicate that the weight gain for that given athlete might not be necessary or desired.
4. Decrease in Performance and Decrease in Body Weight:
In the case of weight loss and performance loss, we can find a negative situation, contrary to Scenario 2, where the weight loss was paired with an increase in performance. In this case, the weight loss comes with a decrease in performance, which could indicate that the athlete is losing muscle mass or the weight loss is putting that athlete under excessive stress. In either case, this can help coaches monitor athletes who might have weight loss tendencies during the season and help the nutrition and medical staff in the monitoring process.
5. Maintenance in Performance and Changes in Body Weight
In the scenario of performance not improving in the presence of body weight changes, we can find two different situations for either gain or loss. If performance is not climbing, we can probably assume that our training is not producing the desired outcomes; however, it is worth mentioning that performance will not always increase, especially when we are training highly experienced athletes. This can be a very likely scenario, which is also why tracking different performance metrics might be a good idea to monitor different athletic actions.
In the two cases shown in the graphs, the first represents an increase in BW with no changes in performance. As indicated, this can be a good or a bad thing; in the case of an athlete gaining weight for purely speed performance purposes, this is a negative result; however, in the case of an athlete who needs to increase weight for contact sports, this might be an expected outcome (not good, but expected).
The second graph shows a decrease in BW with a maintenance in performance; once again, every case is its own world, but in most cases, a desired reduction in BW is expected to come with an increase in most performance parameters that depend on the total mass of the athlete. In the case that the weight loss was undesired, and there was a health concern, this would also be bad news, as the “overall performance” is technically decreasing if the athlete can’t perform better at a lower body weight—which could mean that the weight loss is linked to underlying health issues or causing them.
Applying the Ratio
Body weight is key in all sports; in this case, we cover its importance in athletic actions dependent on the athlete’s mass. As sports performance coaches, we often look to track metrics to understand how to classify our athletes and how to modify their training to help their athletic performance. The BW-to-performance ratio bridges a connection between performance, well-being, and health and facilitates the collaboration between the sports performance and athletic training departments. It also serves as a resource for team doctors to look into when needed.
The BW-to-performance ratio bridges athlete performance, well-being, and health and facilitates the collaboration between the sports performance and athletic training departments. Share on XLet’s apply this in context. I’ve had a very common situation arise with several of my athletes—in this case, after a summer break of 30 days, an athlete came back with a 20-pound drop in body weight, which raised the concerns of the coaching staff and the medical team. We evaluated previous data and closely monitored new data during the first weeks of training. The data is below:
As you can see, there are negative trends in the ratio; however, this real situation becomes much more challenging to analyze than the previous examples. Starting with the overall change in ratio, it is clear that there is a downward trend, which means a negative impact on performance. However, if we take a closer look at the ratio changes before and after summer break, it is clear that the significant drop in BW did not negatively influence performance as much as we expected. This could be taken as a good sign for the medical team, although more observations would need to be made by the rest of the staff.
To wrap it up, let’s review the key points:
- Athletic performance is highly dependent on body weight. It is a good idea to track body weight in coordination with KPIs.
- Strength ratios are for athletic performance what the BMI is for health monitoring: they miss too much information to be used accurately.
- The BW-to-performance ratio bridges testing for performance and health.
- Compare this ratio to outcome metrics if you have force plates. Use relative metrics for a more detailed perspective on force production.
- A performance increase is always a good scenario; weight fluctuations are the reason to monitor this metric.
- Implement this metric in conjunction with sports performance and sports medicine.
I have a full video reviewing this topic on my YouTube channel for those interested in further elaboration and context.
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…we have a small favor to ask. More people are reading SimpliFaster than ever, and each week we bring you compelling content from coaches, sport scientists, and physiotherapists who are devoted to building better athletes. Please take a moment to share the articles on social media, engage the authors with questions and comments below, and link to articles when appropriate if you have a blog or participate on forums of related topics. — SF
References
Castillo M, Martínez-Sanz JM, Penichet-Tomás A, et al. “Relationship between Body Composition and Performance Profile Characteristics in Female Futsal Players.” Applied Sciences. 2022;12(22):11492.
Esco M, Fedewa M, Cicone Z, Sinelnikov O, Sekulic D, and Holmes C. “Field-Based Performance Tests Are Related to Body Fat Percentage and Fat-Free Mass, But Not Body Mass Index, in Youth Soccer Players.” Sports. 2018;6(4):105.
Sansone P, Makivic B, Csapo R, Hume P, Martínez-Rodríguez A, and Bauer P. “Body Fat of Basketball Players: A Systematic Review and Meta-Analysis.” Sports Medicine – Open. 2022;8(1).
Since you’re here…
…we have a small favor to ask. More people are reading SimpliFaster than ever, and each week we bring you compelling content from coaches, sport scientists, and physiotherapists who are devoted to building better athletes. Please take a moment to share the articles on social media, engage the authors with questions and comments below, and link to articles when appropriate if you have a blog or participate on forums of related topics. — SF
The emphasis on individual consent and privacy in data collection is crucial for athlete comfort and autonomy. Rethinking strength metrics to align with the dynamic demands of sports is essential for more accurate performance assessment.