Research Review By Jessica Sleeth ©

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Date Posted:

April 2011

Study Title:

Agonist-antagonist paired set resistance training: A brief review

Authors:

Robbins DW, Young WB, Behm DG, & Payne WB.

Author's Affiliations:

School of Human Movement and Sport Sciences, University of Ballarat, Ballarat, Australia (Robbins, Young, & Payne); School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, Canada (Behm).

Publication Information:

Journal of Strength and Conditioning Research 2010; 24(10): 2873-2882.

Background Information:

Agonist-antagonist paired sets (APS) are when agonist and antagonist muscle groups work in alternating sequence. An agonist muscle works to produce the action and an antagonist muscle works to oppose the action – for example, during a bicep curl, the biceps brachii work to produce the curl (agonist) and the triceps brachii work to oppose the action (antagonist).

The purpose of this review is to discuss possible benefits of APS training, underlying mechanisms, implications for acute performance enhancement, and the use of APS training to potentially improve strength and power. This review focuses on heavy resistance, or ballistic exercises, coupled in agonist-antagonist paired sets. The authors will also examine the practicality of APS and propose future research.

Pertinent Results:

Terminology: Why paired sets?

Common terminology for APS training includes: complex training, compound training, and supersets – with supersets being the most commonly used. Using superset training methodology usually implies that groups of exercises (2 or more) are performed consecutively either targeting opposing or the same muscle groups. The authors argue that the term superset is too vague and therefore introduce agonist-antagonist paired sets.

Previous empirical research describes APS-like training as complex, superset, and paired set training. In the literature, complex training is cited commonly, yet it differs from APS as it couples biomechanically similar exercises and performance is enhanced through post-activation potentiation (1). The purpose of this review is to argue for the implementation of a standard term (APS training) for exercises that focus on agonist and antagonist muscle groups working in a sequential fashion to develop strength and power.

Proposed benefits of paired sets:

APS training is cited as a means to increase power output (2) while improving athletic strength and power (3).

Acute enhancement of power output:
Baker and Newton (2) conducted a trial with 24 male athletes (rugby players), where an increase in power output was observed during the bench press throw 3 minutes after a set of ballistic bench pulls, compared to a trial of bench press throws with no ballistic intervention (2). The researchers (2) hypothesize that the antagonist preloading altered the triphasic firing pattern during the agonist phase. However, a causal relationship cannot be suggested because no mechanistic evaluation was used (i.e. electromyography [EMG]) (2). Other possible influencing factors include the potential of an inadequate warm-up and different rest intervals for the experimental group versus the control group (2).

Robbins et al. (4) tested a sample of trained university-aged male athletes using bench pulls followed by bench press throw (APS). Their results indicated no significant changes in power output or differences in electromyography activity when comparing the intervention trial to the control (traditional protocol – complete all bench pull sets followed by bench press throw sets). However, the authors note that the triphasic firing pattern would not be affected during a non-ballistic intervention (4). The difference in power outputs seen between Baker and Newton (2) and Robbins et al (4) may have occurred because, Robbins et al (4) employed a non-ballistic intervention (low repetitions, i.e. repetition maximum bench pulls) compared to Baker and Newton (2) whose intervention was comprised of 8 ballistic bench pulls.

A trial designed by Maynard and Ebben (5), sampled trained male collegiate athletes, using isokinetic knee flexion and extension exercises. When the antagonist muscle was pre-fatigued, Maynard and Ebben (5) report a decrease in peak power output in the agonist muscle (5). The EMG indicates increased activity in the antagonist muscle, which may be responsible for the decreased power output (5). The authors make note that the intervention warm-up included static stretching, which is not generally advised prior to performance. Further, it is possible that it is not appropriate to compare power output responses, and the mechanisms, of the lower and upper body.

The authors conclude by highlighting that Baker and Newton’s (3) intervention was the only reviewed intervention that exhibited an increase in power output. Thus, it seems likely that intervention protocol influences the results, however, it is most likely a premature conclusion.

Strength and power development:
Trained, male collegiate athletes participated in an 8-week APS training period to test 1-repetition maximum (1RM) bench pull and press, throw height, peak velocity, and peak power (6). The intervention group was compared to a similar group using a traditional protocol (completing all pull exercises prior to push exercises). The group following the APS protocol showed statistically significant increases in 1RM bench pull and press, yet the increases in power were not statistically significant (were similar to that of the traditional protocol) (6). Thus, the researchers suggest that APS may be appropriate for strength development, but not power improvement (6). This study is currently the only longitudinal(-ish) study to date, thus it is difficult for the authors to make strong conclusions. However, it is important to highlight the statistically significant increases in strength reported in the APS intervention, regardless of a small sample size (6).

Efficiency:
The authors believe one of the most exciting aspects of APS training is the possibility of time efficient strength and power development. Efficiency calculations in reviewed studies (3, 5, 6) established that APS training is more efficient than traditional methods of fatiguing the agonist muscles prior to the antagonist muscles.

Proposed mechanisms:

The mechanics of APS training are not well understood; therefore, the authors will attempt to explore changes in the triphasic firing pattern, fatigue, coactivation, and contractile history.

Fatigue:
Muscular fatigue is generally defined as a decrease in the capacity to generate force, which is associated with neuromuscular and metabolic processes (7). Metabolic fatigue includes metabolic byproducts, such as from the Na+/K+ exchange, and non-metabolic fatigue includes myofibrillar disorientation and cytoskeletal damage (8). It can be argued that APS training is more fatiguing than traditional training since antagonist work is performed during the agonist rest intervals. Previously, the authors hypothesized that APS training increased strength over power, which is also considered when reviewing differences in level of fatigue. Increased levels of fatigue in power development training would impact movement velocity and thus attenuate power improvements. It is possible that increased fatigue due to APS training may work to facilitate strength development during an extended training period. Fatigue may act as a stimulus to increase strength, as trials with no rest between intervals show greater strength improvements than those with rest periods. It is speculated that a reduced volume load, due to fatigue, may increase strength over an extended training period.

Coactivation:
Coactivation occurs when the agonist and antagonist muscles simultaneously activate. When agonist muscles fire, the antagonist muscles respond by slowing the movement. Coactivation is thought to increase control of the movement, stabilize the joint, control limb position, and potentially prevent injury. Several aspects of coactivation are explored by the authors – altering the triphasic firing pattern, pre-fatigue of the antagonist muscle, and enhanced activation of the agonist muscle. The triphasic coactivation pattern may be altered by preloading the antagonist muscle. This may decrease antagonist burst and consequently enhance the agonist burst, thereby increasing performance. However, Baker and Newton (2) did not monitor EMG activity during the trial, making this hypothesis only suggestive. Pre-fatiguing the antagonist may work to decrease resistance to the agonist muscle, thus improving power and performance. Not all of the reviewed studies share the same results indicating influencing factors such as load and type of contraction, training status, training and chronological age, genetics, anthropometry, relative, and absolute strength. The mechanisms behind coactivation are generally accepted, however, the role that APS has in influencing coactivation remains speculative.

Exploitation of paired sets:

APS training is hypothesized to increase power output in the short-term and through chronic adaptations to improve performance.

Acute enhancement of performance:
Several factors must be considered prior to attempting to increase acute performance: type of contraction, intensity, volume, rest intervals, and responses of muscle groups. Also of high importance is the individual variability which can be affected by training status, training and chronological age, genetics, gender, relative and absolute strength. Further research is required to determine the efficacy of APS training and acute performance enhancement.

Strength and power development:
Many of the same variables as mentioned above need to be investigated prior to implementing APS training to develop strength and power.

Clinical Application & Conclusions:

APS training may not be an effective means to enhance acute performance. As discussed previously, evidence supporting preloading the antagonist muscle to enhance performance is limited, thus further research is required. If manipulating the pre-competition load on the antagonist muscles is shown to improve performance, several aspects of feasibility are introduced - for example, individual athletic profiles, availability of equipment at competition site, coordination of preloading exercise to competition time, and the cumulative effects of repeated trials. Numerous trials would need to be conducted to determine the transferability of performance enhancement (if found) to determine whether APS training is activity-specific.

The evidence may be limited, however, the authors believe that APS training is an efficient method to increase strength and power. Further research is necessary to determine the different effects APS training may have on strength and power. Presently, APS training appears to be more appropriate for strength rather than power training. APS training is a more time efficient than the traditional training protocol and can safely be recommended to athletes who are concerned about time with respect to resistance training.

The authors conclude the review by sharing further research questions that should be investigated before committing to an APS training program. Additional areas to research include: acute power improvements in upper and lower body; whether APS training is appropriate for strength and power development; and will APS training result in hypertrophy.

Study Methods:

This study is a narrative review of a limited amount of relevant published evidence.

Additional References:

  1. Robbins DW. Postactivation potentiation and its practical applicability: A brief review. J Strength Cond Res. 2005; 19:453-458.
  2. Baker D, Newton RU. Acute effect on power output of alternating an agonist and antagonist muscle exercise during complex training. J Strength Cond Res. 2005; 19:202-205.
  3. Robbins DW, Young WB, Behm DG. The effect of an upper body agonist-antagonist complex resistance training protocol on volume load and efficiency. J Strength Cond Res. In press.
  4. Robbins DW, Young WB, Behm DG, Payne WR. The effect of a complex agonist and antagonist resistance training protocol on strength and power output, electromyographic responses and efficiency. J Strength Cond Res. 2010; 24:1782-1789.
  5. Maynard J, Ebben WP. The effects of antagonist prefatigue on agonist torque and electromyography. J Strength Cond Res. 2003; 17:469-474.
  6. Robbins DW, Young WB, Behm DG, Payne WR. Effects of agonist-antagonist complex resistance training on upper body strength and power development. J Sport Sci. 2009; 27: 1617-1625.
  7. Barnett CH, Harding D. The activity of antagonist muscles during voluntary movement. Ann Phy Med. 1955; 2:290-293.
  8. Green HJ. Mechanisms of muscle fatigue in intense exercise. J Sport Sci. 1997; 15: 247-256.