Strength to Body Weight Ratio and Metabolic Efficiency

Dr. Jeff Casebolt

Please reference the previous edition of Carolina Fire Rescue EMS Journal – volume, issue, story Health Related Components of Physical Fitness, as a precursor to the current article.

Before we progress to Skill-Related Components of Physical Fitness, I would like to take a step back and discuss a few concepts prior to moving forward. Please note two variables I emphasize as a byproduct of training for Muscular Strength when working with athletes are: 1. Strength to Body Weight Ratio and 2. Metabolic Efficiency. These derivatives of Muscular Strength Development need to be mentioned because, in my opinion, they are the link between all other components and are significantly important in the development of sustainable athleticism while minimizing injury potential. Many years ago, I asked a question to no one in particular but was interested in knowing more about training for Maximal Strength, given most of the strength programming, especially among our high school-aged athletes, centered around load-based training and 1RM testing. At the time, all I had ever seen from load-based strength programming was poor technique resulting in high injury rates both within the weight room and as accessory injuries during a bout of competition: practice or games. The thought that I kept coming back to was, “what is more important when training athletes increased Maximal or Repetition Strength”? Upon examination, strength training with an emphasis on developing Repetition Strength, also known as Muscular Endurance, was more advantageous when working with the majority of athletes in the weight room, regardless of sport. Of course, there are exceptions; however, the outliers are in the minority and given the nature of most sports and physical occupations, the ability to produce sustainable force for an extended period of time is more desirable than producing an elevated 1RM or training for Maximal Strength given the nature of the business or sport(s) being played. 

Upon exploration and many years of trial and tribulation, I discovered the percent difference between training for Maximal Strength and Repetition Strength when utilizing undulating strength programming is more closely related than different. It was during this timeframe of my career; that I discovered the two components: Muscle Strength and Muscle Endurance, were more interdependent than previously thought; therefore, my objectives started to shift towards helping athletes to become more resilient and less prone to injury, which in turn allowed the firefighter to refine their skill development. As a result, effort- versus load-based strength programming became the clear objective, with the minimum number of repetitions programmed as five but subjected to change based on the experience and objective of the firefighter. It has been my experience that training loads of five or fewer repetitions tend to unnecessarily subject joint loads to the edge or beyond human tolerance and can result in compensatory movement patterns, which may increase the likelihood of chronic accessory injury. 

A related concept I explored at the same time was the comparison of Strength versus Hypertrophy with the intention of understanding it is possible to increase muscular strength without developing hypertrophy. The reason for this line of thinking was because mass added to the body, in the form of muscle hypertrophy, is more likely to hinder athletic development until the developed strength is able to “catch up” to the added mass in the form of strength to body weight ratio. Furthermore, most strength training programs that I grew up with and were designed for our young athletes were what would be considered hypertrophy based. For these reasons, I started to explore concepts for Muscular Strength development for athletes with minimal or unnecessary hypertrophic effects. If my main objective is to improve athleticism and increase mass through hypertrophic-based strength programming has been shown to negatively affect strength-to-body weight ratio, I realized I needed to shift time in the weight room towards increased strength while monitoring strength-to-body weight as the desired variable when working with the service industry. 

My goal became preparing firefighters for the call of duty and not building mass in the weight room to look good for the next calendar shoot… building mass has shown to not always transfer well to the on-the-job demand. Therefore, the question became how much volume is necessary when working with firefighters given this paradigm shift? Volume equates to the number of sets, reps, and loads an athlete is subjected to during a session in the weight room. No matter the time of year, my objective is to minimize time spent in the weight room to maximize the opportunity for skill development. Research and anecdotal evidence support a minimum of one, maybe two lifting sessions per week, based on the firefighter’s ability to properly recover – minimal dosage suggests as little as one programmed strength day every 10-14 days is enough for maintenance of strength. Adding a third day of strength training per week is only encouraged for advanced lifters who have perfected the art of proper recovery. Often if the firefighter is interested in extra or additional time spent in the weight room, I will often throw a curveball in the form of a mobility session: yoga or Pilates. The lack of mobility, previously addressed, is a significant contributor to chronic injury. The duration of the strength sessions should not exceed 45 minutes at to start, and with time spent and efficiency, strength sessions can be reduced to 30-35 minutes. Each of the traditional major muscle groups needs to be addressed without excluding the following areas of the body: handgrip, forearms, cervical, and ankles – specifically the lateral compartment of the shank. The formula I follow in the weight room is: S-R-A – in other words, how much Stimulus (S) is necessary to put the working muscle(s) into Recovery (R) for the purposes of the desired Adaptation (A)? The stimulus or demand on the working muscle must be great enough to force the working group of muscles into recovery… once this threshold is crossed, then additional volume leads to unnecessary muscle damage, additional recovery time is needed, and the result is more likely going to lead to hypertrophic muscle gains and possibly chronic injury. 

The next question that needs to be addressed is how much volume is necessary to take an athlete through the S-R-A formula – the honest answer is it depends on the athlete and several variables. As a clinician, when I work with firefighters as athletes, I try to get a “feel” for their tolerance in the weight room and stress the importance of stimulus for the purposes of needing recovery and an understanding of the desired adaptation. 

Today, I am no longer concerned with “how much load” an athlete can lift – 1RM testing has no place in my weight rooms. My sole focus when strength training firefighters has become how are you feeling right now, how much time do you have to properly recover before your next significant event, including are you in a position to be called into the field, etc., and how close to momentary volitional failure (MVF or muscular failure) – the inability to complete another repetition with “good” technique in concentric phase – can I take you today? 

When programming strength for a firefighter, I peek at their calendar and ask loads of questions with an understanding of Maximal Recovery Volume (MRV) – in other words, how much stress can I add today in the weight room and still have the athlete prepared for their next event, workday, scheduled workout session, etc. I know that if I take an athlete to MVF with one set, no matter the number of repetitions, there is little doubt there is enough stimulus to put the targeted group of muscles into recovery. However, it is not always ideal for taking the firefighter to complete MVF given the nature of the occupation, and research suggests that getting within 3-5 repetitions of MVF is close enough to put the muscle(s) in recovery for the purposes of adaptation. The concept is widely accepted and has recently been termed stimulating reps, which have been shown to be the reason the working muscles are put into recovery mode, and the recovery time is minimized by not working on completing MVF. As a result, it is possible to get the biggest bang for your buck – increase strength through neurological adaptation, minimize hypertrophy gains, and minimize recovery time for the purposes of skill development, chronic injury potential, and job preparedness.

In addition, with a strength program focused based on effort for the increase in Repetition Strength, an immediate byproduct is metabolic efficiency at the local or muscular level, which pays dividends for improving total work capacity, allowing your athlete more time, repetitions, and opportunities for skill development. This improved metabolic byproduct is especially true once your athlete learns to push themselves to near or full MVF on a consistent basis when proper recovery time is available. The result is an increase in Lactate Threshold, an anaerobic measurement that measures the accumulation of lactate in the blood and is often associated with the onset of fatigue. If fatigue is delayed due to the shuttling of lactate out of the working muscle, keeping the muscle primed to perform, the result is an increase in VO2 max, which is one reason the aerobic and anaerobic bioenergetics are interactive and not on the opposite ends of a conditioning continuum. As a result, the response at the local level improves the work capacity of the exercising muscle due to improved metabolic efficiency, and the firefighter can sustain higher amounts of output for extended periods of time. 

One final thought – Effort-based lifting and strength programming for Maximal and Repetition Strength is difficult to teach, but once installed and your occupational athletes gain an understanding of your intent and purpose, then it becomes a powerful tool. The firefighters show ownership and, as a result, increase their effort in the weight due to the fact that they have a clearer understanding of the objectives. However, because I do not perform any 1RM testing, strength to body weight ratio is a best guess estimation, not an exact measurement, and can change from workout to workout. Therefore, if you choose to adopt effort-based strength programming for your athletes, there is more room for improvement; however, it takes more effort to establish the culture.  

With an emphasis on Muscular and Repetition Strength development to near or full MVF for minimal sets (1-2), reps (5-15), and possibly load (based on the competency of your lifting athletes), strength to body weight ratio is increased through an improved neuromuscular relationship, hypertrophy is minimized due to a decrease in strength training volume, and improved metabolic efficiency is enhanced because of physiological changes at the local or muscular level. 

Jeff Casebolt has been associated with the fitness industry since 1991, working as a personal trainer, strength and conditioning coach, and corporate fitness coordinator prior to going back to school to work on a Ph.D. in Biomechanics and as a professor. Jeff’s research interests include increasing function with strength training across all ages, occupations, and abilities, lower body power development, injury mechanisms among athletes and occupations, and fall prevention among the elderly. In addition, Casebolt is associated with Dynavec Resistance Systems and the Fire Fit Trainer, assisting with research, development, marketing, and sales. 

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