[This is a guest blog by Earl Wilcox. Earl is a graduate from the Kinesiology program at the University of North Carolina at Greensboro. Earl currently possesses his CSCS from the NSCA and is an Applied Sports Science Intern at Athletic Lab.]
Beta-hydroxy-beta-methylbutyrate (HMB) is a supplement that is a byproduct of the breakdown of the amino acid Leucine, which plays a vital role in the regulation of protein synthesis. It is because of this relationship that HMB could help improve performance. There is no magic bullet when it comes to supplements and HMB is no different. However, there are a few circumstances in which it could assist athletes in performing better.
Why would you need a supplement like HMB if Leucine is readily available in foods rich in protein, specifically animal proteins? The reason is that during the breakdown of Leucine, only 5% is converted into HMB (Wilson et al., 2013). To reach the recommended daily dosage of 3 grams of HMB, one would have to consume 600 grams of protein to reach this dosage, which would be the equivalent of 5.5 pounds (88 ounces) of steak throughout the day. There is a restaurant in Texas that will let you eat for free if you can eat their entire 72 oz. steak dinner in one hour. Pictured below is the size of their steak; now imagine having to add an additional pound to that steak. (Picture of steak) While this certainly might be a delicious option for some, it would not be sustainable from a caloric intake standpoint because that amount of steak would have a caloric price tag just shy of 6,800 calories! This would not align with our goal of increasing athletic performance due to the increase in size one would see with that level of protein consumption.
Currently, there are two forms of HMB supplementation: HMB-Ca, which is the most commonly used and studied version of HMB, and the newer version HMB-FA. HMB-Ca tends to be a powder and taken in pill form whereas HMB-FA tends to be a gel. The only difference between these two supplements is the FA version will reach its peak level faster and have a higher peak than the Ca version. To illustrate this point further, see the picture below (Graph of HMB concentration). Another perk to the FA version is, despite its elevated concentration, it is not excreted in urine at a higher rate and is utilized 25% more effectively than its Ca counterpart (Wilson et al., 2013). Although the Ca version was the one used in most previous research and has the most data available, most current and future research focuses on the HMB-FA form.
The research indicates a couple of areas where supplementing HMB may prove beneficial for increasing performance. The first is its ability to possibly aid in recovery. One study looked at how HMB could possibly attenuate some of the muscle soreness that is seen with resistance training and how this affects the way a person feels following training. To measure this, the participants’ creatine kinase levels were measured and a Perceived Recovery Scale (PRS) was used to monitor how they felt 48 hours following training. The PRS scale is based on the individual’s physical and mental feelings prior to a training session and can be an effective tool for examining the recovery after training before starting the next session. Creatine kinase is an important measure because it is an indicator of muscle damage following intense training. While the HMB users and the placebo group both had creatine kinase level greater than baseline, the HMB group had only a 104% increase over baseline and the placebo group had a 329% increase. When comparing the PRS data between the two groups, they both experienced similar PRS scores immediately following training. The difference between the two was that the HMB group had PRS scores higher than the placebo 48 hours following the training session, meaning that they felt more recovered than the placebo group (Wilson et al., 2013)
HMB can also have a protective effect on the muscle during times of inactivity. A study was done in the elderly which indicates potentially similar effects on athletes who are seriously injured and require surgery. This study looked at the effect of 10 days of bed rest in an elderly individual. This length of bed rest leads to decreases in both lean tissue and strength in the lower body. While there was no significant change in either the HMB or placebo group in terms of overall body mass, there was a difference when looking at the lean mass lost. The HMB group lost roughly 0.9% of their lean mass, while the placebo group lost 1.4%. This particular loss of lean body mass is greater in older people than it would be in young adults when they are put on 14 or 28 days bed rest, which is important to consider when looking at how it might affect younger individuals going from active to inactive due to injury (Deutz et al.,2013).
The final study I looked at was a 12-week supplementation of HMB and how it affected muscle mass, strength, and power in resistance trained individuals and, specifically, if HMB was able to attenuate the performance decreases seen during overreaching when the diet was being controlled. The resistance training for this study was a non-linear periodized model for the first 8 weeks, following that there was a two week overreaching cycle followed by a two week taper. Following this training protocol, the HMB group saw an increase in strength of 77.1 kg over three lifts (bench press, squat, deadlift), while the placebo group only saw a 25.3 kg increase. The HMB group also saw an increase in Wingate and vertical jump test compared to the placebo: 18% vs 12% increase in Wingate and 19% increase vs 12% in vertical jump respectively. Finally, the HMB group also saw a decrease in body fat when compared to the placebo, with the HMB group losing 5.4kg versus 1.7kg. So, not only did the HMB group get stronger and more powerful, they also got leaner (Wilson et al., 2014).
While research is an important part of discovering how to increase performance in a lab, it means nothing unless practitioners can find a way to implement these supplements effectively in the practical setting. There are a few examples where HMB might be most efficiently used. The first is in sports where there are weight restrictions, such as combat sports. The reason is that these sports normally require drastic weight losses in order to compete, however, the loss of lean tissue could have a negative impact on performance both long and short term. The short term impact is because lean tissue is important in generating large amounts of force and can be the difference between winning and losing. The long term implications stem from the ability to make weight constantly, which also stems from the ability to maintain lean tissue. When a person has increased amounts of lean tissue, it helps them maintain weight because it is living tissue that requires energy. Not only will this help prevent extra weight gain but it will also allow for easier weight loss, thanks to an increase in basal metabolic rate. Creatine, which is another supplement that could help increase performance in these athletes, can have an unwanted side effect of causing the body to hold onto water. While in most sports, this would not be an issue, it would be in combat sports because cutting water weight is how a lot of athletes make their weight. The final reason HMB would be a strong choice for these athletes is the psychological effect it can have as it pertains to recovery. As the research states, the perceived recovery was increased in those who took HMB. This cannot be underestimated for these athletes who are notorious for having grueling and intense training camps and weight cuts for upcoming fights. The ability to feel more recovered during these times should definitely allow for better performance during training, which in turn should lead to better performances during competition.
The final practical example would be for athletes who have sustained an injury that requires significant down time, particularly in helping the athlete maintain lean tissue during a time where they will be unable to train as effectively as they could if they were healthy. If an athlete is able to mitigate the loss of lean tissue to the affected area, they should be able to return to their previous form more quickly because less time would be spent gaining lean tissue back. It should also be noted that it will help with the return to training as well because HMB helps reduce the amount of creatine kinase created during physical activity, which is linked to the amount of damage done to the muscle fibers. Therefore the athlete should see quicker recovery times and less soreness when reintroduced to training, which should allow for less time between each training sessions. One aspect that should not be overlooked, is the psychological benefit of decreasing the soreness the athlete feels as well as their perceived recovery, which could create greater buy-in to the training program from the athlete.