By: David Larson, MS, CSCS,*D, Pn1
- Most fitness centers and trainers claiming to offer functional training are doing so purely for marketing purposes. Don’t fall prey to marketing hype from uneducated trainers and gyms, especially when they don’t practice what they preach.
- Research indicates that the introduction of instability to traditional exercises actually limits increases in functional measures.
- Functionality exists on a spectrum and is highly variable in every individual.
- Unstable surface training and popular “functional exercises” should probably not comprise the majority of your workout. Stick to the major lifts when possible. Supplement with unstable surface training and other exercises when appropriate.
- As far as results go, training using the principles of progressive overload will trump “exercising” any day.
Functional training has become the new buzz-term in fitness. Gyms and fitness centers across the country are suddenly in a race to become more functional than their competition. Traditional lifting equipment is being displaced to make room for suspension straps, wall balls, and empty space to perform body weight exercises. A quick google image search of “functional training” results in a series of pictures of BOSU ball exercises, barbell back squats on exercise balls, TRX push-ups, and many more balance/stability related exercises. This is a large shift away from more traditional weight training programs. Although many of these balance and stability exercises that are typically associated with functional training may look challenging, fun, or novel, they may not actually be functional. Furthermore, they typically are not performed in a progressive manner that would actually lead to functional gains in muscle mass, force production, and subsequent physique enhancements.
Functional fitness has previously been defined as “having the physical capacity to perform activities of daily living in a safe and independent manner without undue fatigue (Schoenfeld, 2010).” A common component of most exercises that are deemed functional involves unstable surfaces. Proponents of unstable surface training note that the unstable surface challenges the neuromuscular system to a greater extent than stable surface training, thereby maximizing muscular adaptation. Although the use of balance and stability training is of great use in a rehabilitation setting; there is little evidence that unstable surface training leads to greater enhancements in functional fitness than traditional exercise programs.
What does the research tell us?
Cressey, West, Tiberio, Kraemer, and Maresh (2007) evaluated the effects of ten weeks of lower-body unstable surface training on markers of athletic performance. Nineteen healthy male Division 1 college soccer players supplemented their normal conditioning program with lower-body exercises on either an inflatable rubber disk (US) or on a stable surface (ST). The ST group improved significantly on the bounce drop jump and the countermovement jump tests; however, the US group did not. Additionally, the ST group improved significantly more than the US group in 40-yard sprint times and equal improvements were noted on the T-test. The authors concluded that substituting stable surface training for unstable surface training attenuates performance improvements in healthy, trained athletes.
Another study by Christou et al. (2006) evaluated the effects of resistance training on the physical capabilities of adolescent (age 12-15) soccer players. Specifically, the authors compared a combined strength training and soccer group (STR) and a soccer only group (SOC) with a non-training control group (C). The program included 10 exercises of 2-3 sets of 8-15 repetitions operating on a linear periodization model. Exercises for the STR group consisted of leg press, bench press, leg extension, peck-deck, leg flexion, overhead press, lat pull-downs, calf raise, sit-ups, and upper-lower back extension (clearly not functional, right?). Players followed a 5 day per seek soccer training program, with the STR group adding the resistance training before practice 2 days per week. Pre- and post-training measurements in flexibility, 10 m sprint time, 30 m sprint time, 10 x 5 m sprint times, mean height of repeated jumps for 30 s, soccer technique tests, squat jump height, counter movement jump height, leg press 1RM, and bench press 1RM. The results indicated that the STR group improved maximal strength, physical capacities, vertical jump performance, and 30 m sprint speed improved more than the SOC group.
The results of Christou et al. (2006) are interesting. The authors demonstrated that a basic resistance training protocol consisting of slow-speed movements transferred positively to certain plyometric and speed skills, such as the vertical jump and 30 m sprint. No BOSU balls or acrobatic TRX maneuvers required.
Stepping away from healthy athletes, traditional strength training methods such as the leg extension have actually been shown to lead to enhancements in functional training. For example, Fiatarone et al. (1994) found that 3 sets of 8 repetitions of leg extensions improved quadriceps strength by an average of 174% and increased functional scores by approximately 48%. Although there was no comparison to a similar balance training group, the results of Cressey et al. (2007) suggest that inducing instability would only suppress gains in muscular strength that positively transfer to functional capacity.
So what does that all mean?
Why is there such a discrepancy between the strength gains made with traditional stable weight training and modern functional training programs? Although there are several factors at play, the differences likely are a result of the “progressive overload” principle. Progressive overload can be defined as a gradual increase in the stress placed on the musculoskeletal system over time. This slow increase in musculoskeletal stress ultimately culminates in an increase in muscle size, strength, and functional capacity. During traditional stable weight training, it is much easier to adequately apply tension to the desired muscles. Think about it. How much more weight could you deadlift on a stable surface than on a BOSU? A LOT MORE. Lastly, the mechanisms that lead to muscle growth have been well established, and indicate that mechanical tension, muscular damage, and metabolic stress all stimulate hypertrophic adaptation. Thus, anything that would serve to limit these mechanisms would ultimately delay progress.
Although balance and stability training have their place in any conditioning program, and especially in a rehabilitation setting, strength and conditioning professionals must be aware of the implications of exercise selection. Cressey and colleagues (2007) demonstrated that unstable surface training does not positively transfer to markers of functional performance in athletes; however, stable surface strength training does. Additionally, Christou et al. (2006) demonstrated that traditional strength training improves functional measures for elite soccer players. Moreover, Fiatarone and colleagues (1994) have demonstrated that moderate to heavy load knee extensions (an abomination in the eyes of functional training gurus) could improve functional scores by 48%! Essentially, functional training may not be as functional as many people believe. Strength is functional. Don’t buy into the idea and marketing hype of functional training. Functionality exists on a spectrum, and each individual’s spectrum is different. Progressive and individualized strength and conditioning training is the only true functional training.
Christou, M., Smilios, I., Sotiropoulos, K., Volaklis, K., Pilianidis, T., & Tokmakidis, S. P. (2006). Effects of resistance training on the physical capacities of adolescent soccer players. The Journal of Strength & Conditioning Research, 20(4), 783-791.
Cressey, E. M., West, C. A., Tiberio, D. P., Kraemer, W. J., & Maresh, C. M. (2007). THE EFFECTS OF TEN WEEKS OF LOWER-BODY UNSTABLE SURFACE TRAINING ON MARKERS OF ATHLETIC PERFORMANCE. Journal of Strength & Conditioning Research (Allen Press Publishing Services Inc.), 21(2), 561-567.
Fiatarone, M. A., O’Neill, E. F., Ryan, N. D., Clements, K. M., Solares, G. R., Nelson, M. E., . . . Evans, W. J. (1994). Exercise training and nutritional supplementation for physical frailty in very elderly people. New England Journal of Medicine, 330(25), 1769-1775.
Schoenfeld, B. (2010). Is functional training really functional. ACSM Certified News, 20(3), 5-6.