VARIABLE RESISTANCE TRAINING: DOES USING BANDS ENCHANCE STRENGTH DEVELOPMENT?

Strength can improve many measures of sports performance and reduce the incidence of injuries during athletic tasks. Subsequently, increasing strength is of interest to strength and conditioning coaches and personal trainers in the weight room. Strength is traditionally developed through constant resistance training (CRT) using free weights. With lifts that fall on the ascending strength curve e.g., bench-press, back-squat, and dead-lift (Wilson & Kritz, 2014). The challenge for practitioners is to efficiently develop a client’s strength to allow for optimal performance to be realised. Therefore all appropriate training modalities should be considered for inclusion in training programmes. Currently garnering attention as a training modality that can significantly enhance strength development is variable resistance training using elastic bands (VRT-B) (Ghigiarelli et al., 2009). When bands are attached to free-weights, the lifter is challenged by the variance in tension throughout the entire range of motion (ROM) (Kuntz, Masi, & Lorenz, 2014). Some have questioned the efficacy of VRT-B, arguing that there is limited loading potential compared to CRT. Therefore, some researchers believe that there is limited potential for optimal muscular and neural adaptations to present (Aboodarda, Ibrahim, Mokhtar, Thompson, & Behm, 2012; Stevenson, Warpeha, Dietz, Giveans, & Erdman, 2010). The purpose of this review is to evaluate and discuss the body of research on the use of VRT-B for enhancing strength development in comparison to CRT. To conclude, practical applications and suggestions for future research are discussed.

When conducting CRT with ascending strength curve lifts, acceleration of the load (and therefore average force) is negatively affected due to the sticking point, which is mechanically disadvantageous (Anderson, Sforzo, & Sigg, 2008). The most significant expression of strength occurs at the beginning of the concentric phase, with decreases in force evident after that as the bar approaches maximal displacement (Anderson et al., 2008; McMaster, Cronin, & McGuigan, 2009). Here, the lifter experiences a mechanical advantage due to multi-joint torques. The most considerable force-producing capabilities are in this position (McMaster et al., 2009). The depletion of force experienced during CRT is sub-optimal, with greater adaptations likely to occur if the load could be varied throughout an entire ROM (Andersen, Fimland, Kolnes, & Saeterbakken, 2015).

  Researchers suggest that VRT-B can vary the load throughout an entire ROM, altering the kinetics and kinematics of lifts, and complementing the ascending strength curve (McMaster et al., 2009; Wilson & Kritz, 2014). As the band deforms, higher accelerations are experienced early in the concentric phase. Higher accelerations result in superior average force production due to the progressive recruitment of high threshold muscle fibres and motor units, allowing for more significant expressions of strength at or near full-limb extension (Anderson et al., 2008; Israetel, McBride, Nuzzo, Skinner, & Dayne, 2010; Kuntz et al., 2014; McMaster et al., 2009; Wallace, Winchester, & McGuigan, 2006; Wilson & Kritz, 2014). Additionally, the eccentric portion of the lift is also more challenging due to the bands pulling on the bar and increasing the eccentric loading (Anderson et al., 2008; Israetel et al., 2010; McMaster et al., 2009; Wallace et al., 2006). Hypothetically, VRT-B is a more beneficial training modality to develop strength due to the heightened presence of high-threshold muscle fibres and motor units. It is thought that training with bands can increase firing rates and improve motor unit synchronisation (Kuntz et al., 2014; McMaster, Cronin, & McGuigan, 2010).

The first observation from the literature is that many studies managed to provoke improvements in strength, as noted by increases in strength test measures for bench-pressing and back-squat – 1, 3 and 6RM. Five studies investigated the effects of VRT-B on recreational men and women from varying age ranges and with different levels of resistance training experience. Andersen et al. (2015) observed 25% and 23% improvements in maximal strength in VRT-B and CRT groups, respectively. In contrast, Bellar et al. (2011) witnessed a 2.39 kg greater increase in strength of the VRT-B group over the CRT group, and this finding was statistically significant. Greater improvements across the board were observed by Bicer, Ozdal, Ackan, Mendes, and Patlar (2015); this was also the case for Muller et al. (2009). The one exception was Shoepe, Ramirez, Rovetti, Kohler, and Almstedt (2011) who despite inciting strength enhancement in both groups, observed the most significant improvements with CRT.

  There were only two studies that investigated the effects of VRT-B on athletes. Both studies investigated the effects of a 7-week macrocycle on strength, each demonstrating more considerable strength improvement in the VRT-B groups within the respective studies. Anderson et al. (2008) periodised training across a spectrum of loading assignments – 72-98% 1RM. Irrespective of the training intensity, contribution to overall tension from bands remained constant at 20% (Anderson et al., 2008). 1RM bench-press improved 8% in the VRT-B group as opposed to 4% in the CRT group and back-squat strength increased by 16% in the VRT-B group with CRT only improving by 6%. Ghigiarelli et al. (2009) prescribed undulating periodisation over 7-weeks with two heavy sessions early in the week, followed by two lighter sessions later in the week. While not statistically significant, the VRT-B group did boast the most considerable improvement in 1RM bench-press strength, 8% as opposed to the 5% increase in the CRT group.

It is apparent that VRT-B positively impacts strength development. Subsequently, training with bands is an alternative training method that can be used to develop strength in lifts that fall on the ascending strength curve. Percentage band contribution to the overall training load varied among studies with 15% (Bellar et al., 2011; Muller et al., 2009), 20% (Anderson et al., 2008) and a range of band tension between 20-35% (Shoepe et al., 2011). A percentage contribution of 20-35% is recommended by McMaster et al. (2009) which differs to recommendations by Kuntz et al. (2014) who state 10-15% is best for provoking strength gains. Too low a contribution may prove to be ineffective. Too high a contribution is likely to result in a ceiling effect (Kuntz et al., 2014). 20% seems appropriate; particularly in the athletic population as this has been proven effective in division 1-AA collegiate athletes (Anderson et al., 2008). For practitioners, many gyms have access to resistance bands. The use of bands can be explored to help clients build strength, break down a plateau in strength, and to provide some variety to a client’s training plan. Future research should look to quantify optimal band tension. Effects on different athletic disciplines should also be investigated. Including isometric tests to measure strength improvement at different angles in a ROM, would also help further our understanding of this training method.