The Popularity of Functional Strength Training
Functional strength training has gained popularity recently. Although definitions vary somewhat, functional strength training means performing work against resistance in such a way that the strength gained directly benefits the execution of activities of daily living (ADLs), work or sports performance. In other words, it is focusing on training NOT exclusively for appearance or hypertrophy, but instead for the benefits of improved performance (better golf game, greater vertical jump, enhanced ability to get in and out of the bathtub, etc.). Since functional strength training encompasses ADLs, which affect everyone, it has application to all populations from athletes to seniors.

Research from motor control and learning as well as neuromuscular physiology shows that for strength exercises to effectively transfer to other movements - in essence, to be functional - the training movement must be similar to the actual performance movement. The principle of specificity is essential and supported by the literature. The body will perform best according to the specific type of training imposed on it, including components of training such as muscle-group usage, type of contraction and speed of movement.

Furthermore, coordination also is critical for performance; all body parts used in the goal movement must be trained simultaneously - as opposed to traditional muscle isolation exercises. For example, a standard leg extension helps strengthen the quadriceps, which play a role in powering the running motion. But is there a better way to train against resistance that more effectively transfers to running and thereby enhances performance more directly?

A Revolutionary New Tool
Hammer Strength recently introduced two new machines unlike anything available today: the Motion Technology Selectorized (MTS) Recriprocating Leg Left and Reciprocating Leg Right. Using dual weight stacks and Iso-Lateral movement arms, these distinct pieces require one leg to perform a leg extension while the other leg can simultaneously perform a leg curl, thereby challenging the quadriceps and hamstrings at the same time. This simulates the leg motions used in walking, running, cycling and swimming.

Therefore, the user must synergistically work opposing muscle groups and force the neuromuscular system to adapt to this motion against a workload. The result is a movement that feels more natural, mimics real-life motion and thereby better transfers to ADLs and athletic endeavors.

Various research studies support the benefits of this type of synergistic opposition training. Much of the improvement seen in the strength of a muscle during a movement is due, in large part, to the increased ability to coordinate multiple muscle groups during the movement (Rutherford and Jones, 1986). Rutherford also noted that the training of appropriate neural patterns is as important to the performance of muscles in skilled movements as increasing the strength of the muscle (Rutherford, 1988). Again, this supports that simultaneous training of the quadriceps and hamstrings can better enhance performance in walking, running, cycling and swimming than can traditional knee extension or flexion exercise.

In another study that examined the effectiveness of training knee extension bilaterally or unilaterally, the authors found that while both variations produced adaptations in the neuromuscular system, "the magnitude of functional strength increases is specific to the type of exercise used, further supporting the principle of specificity in the design of strength programs" (Hakkinene, et al 1996).

Previously, the type of opposition training was available only on isokinetic devices that fix speed of movement but vary resistance throughout the range of motion. Commonly used in rehabilitation settings, isokinetic machines, however, generally are seen as a poor developer of "real-life" strength because they provide only speed-controlled resistance, instead of gravity-based resistance. Improvements in strength grained from isokinetic training have shown to have little carryover to the same movements on isotonic weight training equipment (Morrissey, et al 1995).

Researchers also concluded that training on isokinetic equipment led to a performance improvement on isokinetic equipment - and not necessarily to improvements on standard isotonic weight training equipment (Morrissey, et al 1995). Therefore, training on standard weight machines (which factor in eccentric contractions and the effects of gravity) versus isokinetic equipment leads to greater functional performance.

The Most Effective Way to Train
So what is the best way to resistance train? Should traditional muscle isolation exercises using tools such as selectorized equipment be abandoned? Should one solely perform functional resistance training exercises using free weights, free movement pulley systems such as the Life Fitness Pro Series Dual Adjustable Pulley System and advanced feet-on-the-ground machines such as Hammer Strength Ground Base? Or must exercisers await the development of other synergistic opposition training equipment like the Hammer Strength MTS Recriprocating Leg Left and Reciprocating Leg Right?

Actually, a smart exerciser will gain the best results by performing different exercises using a variety of strength training tools, from free weights to plate-loaded equipment to selectorized machines. No one tool can provide all the benefits of the others, so variety is essential. Muscles will continue to develop and performance will improve with progressive overload and changes in exercises.

Furthermore, challenging the body with several different training methods such as muscle isolation work and functional exercises generally will produce better overall performance than using one specific method alone. There is great value in muscle isolation exercises (training parts of the whole), and functional strength training is beneficial as well (training the whole to work as a unit).

Certainly, a competitive bodybuilder may limit functional strength training, instead concentrating on muscle isolation exercises for hypertrophy. Conversely, a man in his 40s who is more interested in quality of life versus appearance may concentrate more on multi-muscle, multi-joint functional resistance exercises that enable him to improve his tennis game and better perform ADLs such as putting luggage into an overhead compartment.

The bottom line is that the body responds best to exercise variety. The Hammer Strength MTS Reciprocating Leg Left and Reciprocating Leg Right not only create another unique option to train the legs but help bridge the gap between muscle isolation and pure functional strength training.

References
Cunningham, C. Strengthen Clients for Everyday Activities. Personal Fitness Professional, April 2000.
Hakkinene, K., Kallinen, M., Linnamo, V., Pastinen, U.M., Newton, R. U., & Kraemer, W. J. (1996). Neuromuscular adaptations during bilateral versus unilateral strength training in middle-aged and elderly men and women. Acta Physiol Scand 158, 77-88.
Morrissey, M., Harman, E.A., & Johnson, M.J. (1995). Resistance training modes: specificity and effectiveness. Med Sci Sports Exer 27(5), 648-660.
Rutherford, O.M. (1988). Muscular coordination and strength training. Implications for injury rehabilitation. Sports Med 5, 196-202.
Rutherford, O.M. and Jones, D.A. (1986). The role of learning and coordination in strength training. Euro J. Appl Physiol. 55:100-105.
Interview with Christine Cunningham, MS, ATC/L, CSCS, PerformEnhance Sport and Adventure Training and Ph.D. candidate in exercise neuroscience at the University of Illinois at Chicago, December 2001.