Free-Weight Variable Resistance Strength Training Methods

Free-Weight Variable Resistance Strength Training Modes – Although free-weights are generally considered superior to weight machines when training for explosive strength, researchers and practitioners have for some time recognized an inherent problem when using traditional standard free-weight exercises like the parallel squat and bench press. (5,13,16,17,37,43,44). For example, Elliot et al. revealed that during 1-RM bench press, the bar decelerates for the final 24% of the range of motion (10). At 81% of 1-RM, the bar deceleration occurs during the final 52% of the range of motion. The accompanying deceleration phases results in significantly decreased motor unit recruitment, velocity of movement, power production and compromises the effectiveness of the exercise. Essentially, strength and power are accentuated at the beginning of the movement, but not through the entire range of motion (28).

Partial solutions to the aforementioned problem have included the use of plyometric exercises, as well as Olympic style weightlifting and their variations (9, 24). Plyometrics are considered to have an important advantage over free-weights, because the mass (i.e. body mass, medicine ball) is accelerated throughout the range of motion. Likewise, Olympic-style weightlifting movements, because of their high velocity characteristics and subsequent high power outputs, are also used to train for explosive strength and to evaluate explosive strength in many strength training programs (1,2,6,8,13,14,26). Another possible method is free-weight variable resistance strength training. For the purposes of this article, we will define variable resistance as resistance that changes by increasing throughout all or part of the lifting phase of an exercise and free-weight variable resistance as the two methods in combination, i.e. combined resistance.

Methods of Variable Resistance

Over the years, various solutions have been proposed to compensate for the deceleration phase of strength training exercises. These methods include variable resistance and accommodating leverage machines, iso-inertial machines, as well as combinations of free weights and hydraulics, elastic latex tubing or bands and large chains (5,20,23,28,31,32,38,39). Three very distinct free-weight variable resistance methods will be covered here.

Free Weights - Elastic Resistance

Behm hypothesized that free-weights together with the elastic resistance provided by surgical tubing, would overcome the inherent shortcomings of each, by complementing one another (5). According to Behm, the resistance in elastic tubing will not provide an overload to the muscle at the beginning of a movement, although it does provide increasing or variable resistance throughout the movement. Conversely, free-weights provide resistance and an overload to the muscle at the beginning of a movement, but not later in the movement because of momentum and the corresponding need to slow the weight before coming to the end of the movement. Behm claimed that free weights and the elastic tubing solved the aforementioned problems because the resistance (inertia) of the weight, counters the lack of tension or resistance in the elastic tubing during the initial stages of the movement, and the increasing stretch and resistance of the elastic tubing controls the momentum of the weights and provides the needed additional resistance at the end of the range of motion.

Free Weights - Chain Resistance

Simmons has described a training method using free-weights together with large chains (31,32). The large chains were hung from each end of a barbell using smaller chains. When the bar is lowered, the large chains accumulate on the floor, gradually decreasing the total resistance. When the bar is raised, the total resistance increases throughout the range of motion. Simmons claims this method improves the muscles neurological response and overloaded the top part of the lift, which ordinarily does not receive adequate resistance, with accommodating or variable resistance.

Free Weights - Hydroviscosity Resistance

Telle and Gorman advocated the use of free-weights together with hydraulics (38). They presented the following rationale for the superiority of their method of variable resistance. They indicated that resistance is provided by the weights at the beginning of the concentric phase. In addition, additional force is required during the concentric phase of the movement, because of the clearly reduced coasting due to the weight/hydraulic combination. Higher peak force occurs during acceleration, because the athlete has to overcome both the hydraulics and the weights. Therefore, there is force at the end of the concentric phase because of the weights, which would not be present with hydraulics alone. Furthermore, resistance is present during the eccentric phase, invoking the stretch reflex, which would not be present with hydraulics alone.

Benefits of Using Free-Weight Variable Resistance Methods

The addition of the extra variable resistance allows the individual to "push hard" throughout the range of motion increasing the intensity and specificity of the exercise. Additionally, strength and power accentuation increases. Accentuation can be defined as increasing muscular strength at the position at which maximal efforts are developed during the main sport event, principally near the extreme points of angular motion (46). Finally, following Newton’s Second Law, there should be an increase in the ability to accelerate a mass since the rapidly increasing force that must be applied during training with this method is comparable to the force production required to explosively accelerate a mass under normal conditions.

There are several secondary advantages of using variable resistance methods to develop explosive strength versus other methods. First, the methods can be integrated into any traditional strength training program. The limited time available for training is used more efficiently by reducing some of the need for auxiliary explosive strength exercises. Another advantage of using free-weights and these methods is that higher repetition schemes can be used, compared to the lower repetition schemes that are typically used with Olympic style weightlifting training (30,46). Higher repetition schemes are associated with increased muscle hypertrophy and muscular endurance, or in this case power endurance (3,45). Finally, specific strength training outcomes can be varied by manipulating the amount of weight on the barbell and the amount of extra resistance that is applied, as well as when in the range of motion it is applied.

Training Guidelines

Multi-joint exercises like the parallel squat and bench press can be trained effectively with free-weight variable resistance methods (33,35,39). Other free-weight exercises such as the incline bench and shoulder press can also be trained. The majority of training should take place using moderate intensities of between 60-80% of 1-RM, due to force and velocity requirements, and 3-5 sets of between three to eight repetitions are recommended (1,2,13,17,18,40,42). Contractions should be performed as explosively as possible on all work sets after warming up properly. (4,7,12,19,21,27,36,39). Resistance should be varied using periodization methods and by pyramiding work set weights (11,15). Explosive strength should be evaluated regularly with the appropriate tests (22,24,25,26,41).

Summary

Strength and more specifically, explosive strength is fundamental to successful athletic performance. Free-weight strength training has been commonly used to develop this important ability. The inherent problem with the  deceleration phase of traditional free-weight strength training exercises like the parallel squat and bench press has resulted in a search for more effective methods. Two possible solutions, plyometrics and Olympic style weightlifting have been widely used. A third solution, free-weight variable resistance strength training , has some distinct advantages over the other methods. Among those advantages are increases in accentuated strength and power, along with the ease with which this method can be integrated directly into traditional free-weight strength training programs.

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