PS training, under designations such as “super sets” or “compound sets,” has been prescribed by practitioners as a means of developing strength. It has been suggested by various body-building publications that this type of training is time-efficient without compromising results. In the present study, Bpull and Bpress VL were not different per set, or for the session, under the PS and TS conditions. Efficiency calculations (Table 4) determined PS training to have almost double the efficiency compared to TS training. These findings would seem to support the hypothesis that with respect to PS training efficiency is enhanced because the session time was approximately half with no significant decrease in VL. Comparisons of EMG data across the 2 conditions indicate that the PS protocol had no greater neuromuscular activation deficits than the TS protocol.
Although there were no differences in EMG signal across conditions or from set to set, there were differences from first repetition to final repetition within all sets of Bpress in both conditions in the pectoralis major, anterior deltoid, and trapezius muscles. This was not observed in the latissimus dorsi muscle during Bpress or in any of the 4 monitored muscles during sets of Bpull. This can perhaps be explained by the fiber-type composition of the 4 muscles and the relative involvement of the muscles in the Bpress and Bpull exercises. The percentage of Type 1 (fatigue resistant) fibers in the pectoralis major, anterior deltoid, latissimus dorsi, and trapezius muscles has been reported to be 35, 47, 48 and 44%, respectively (12,20)-that is, among the 4 monitored muscles, the latissimus dorsi is arguably the most fatigue resistant. Furthermore, with respect to the Bpress exercise, it is likely that the latissimus dorsi does not play the major role, whereas, with respect to the Bpull exercise, the latissimus dorsi plays the major role. With respect to the Bpress exercise, the pectoralis major and anterior deltoid are likely the major contributors in this movement.
The contractile response of skeletal muscle is partially determined by its contractile history (13). Because of the nature of PS training, the contractile history of the agonist and antagonist must be considered. Coactivation refers to the concurrent activation of agonist and antagonist muscles (4,16). Unlike the present study, the 2 previous studies that investigated upper body contrast sets (1,3) did so in attempts to augment performance and, as such, utilized different protocols. The coactivation-related mechanisms proposed by the researchers to explain the observed acute performance enhancement are unlikely to have played a role in the present study. Because of the nature of the protocol (i.e., nonballistic-type movements, pauses at the end of the range of motion, and a 2-minute RI between agonist and antagonist exercises) utilized in the present study, and subsequent results, changes in stored elastic energy (3) or the extent of EMG activity (both RMS and MDF) (1) were not a factor.
This study only examined responses of 1 PS (2 exercises) performed over 3 trials (6 sets). Commonly, resistance training sessions targeting multiple muscle groups involve more than 2 exercises and more than 6 sets. Thus, the differences in session VL (Bpull and Bpress) in PS as compared to TS, although not statistically different in the present study, could continue to grow over a longer training session and manifest themselves as significant. Furthermore, it must be acknowledged that the maintenance of a similar acute VL under PS, as compared to TS, does not necessarily yield equivalent, or effective, chronic development of strength over an extended period.
Although VL did not differ between the 2 conditions, VL did decrease from set 1 to set 2 and from set 2 to set 3 in both exercises under both conditions. This would seem to indicate that a 4-minute RI was not adequate for the targeted musculature to recover from local fatigue and maintain the volume of work. Although, to date, there have been no scientific studies reported examining VL maintenance in the Bpull, a number of studies have examined VL maintenance in the Bpress exercise. However, Bpress VL maintenance has not been examined as the second exercise in a training session-that is, following 3 sets of Bpull (TS) or as half of a PS.
The RI necessary to maintain Bpress repetitions would appear to be dependent on the magnitude of the load. Specifically, submaximal (i.e., <90% of 1RM) loads performed to failure would seem to require somewhat longer RIs as compared to maximal (i.e., 1RM) loads (8,27). Weir et al (26) found a 1-minute RI adequate to perform a 1RM over 2 sets. Kraemer (8) found a 3-minute RI was adequate to maintain a 10RM over 3 sets. In contradiction to these findings, Willardson and Burkett (28) determined that a 5-minute RI was not adequate to maintain Bpress repetitions using an 8RM over 4 consecutive sets. Similarly, Richmond and Godard (17) found a decline in repetitions over 2 trials separated by 5 minutes using a load of 75% of 1RM. With respect to the four studies (three described above and the present one) using loads between 70 and 90% of 1-RM, it is possible that the training status of the participants in the study which found repetition maintenance (8) was different than that of the participants in the studies which did not. Specifically, the participants in the Kraemer (8) study were Division 1 American college football players, whereas the participants in the other 3 studies were recreationally trained. It is likely that the Division 1 football players were better adapted to performing maximal effort Bpress over consecutive sets than were the recreationally trained participants. The results of the present study suggest that when Bpress is performed as the second exercise in a training session, or as half of a paired set, greater than 4-minute RIs are required to maintain VL when using a load of less than 90% of 1RM. It would appear this is also the case for the Bpull exercise when performed as the first exercise in a training session or as half of a paired set.
A relatively large body of literature exists examining the relationship between RI length and volume maintenance. However, the literature has predominantly focused on this relationship over repeated trials of a single exercise. Under the TS condition in the present study, VL was monitored over repeated trials of 2 exercises performed 1 after another. Arguably, this structure more closely mimics a true training session as compared to studies that investigated a single exercise over repeated trials. Not only was a 4-minute RI inadequate with respect to maintaining VL over the initial 3 sets of Bpull, but it was also inadequate in terms of VL maintenance over the subsequent 3 sets of Bpress. Because VL in the first set of Bpress was not significantly different between the 2 conditions, it would seem as if the cumulative effects of performing 3 sets of a 4-RM Bpull with 4-minute RIs, prior to the first set of Bpress under the TS condition, were no different than the effects of performing 1 set of a 4RM Bpull 2 minutes prior to the first set of Bpress under the PS condition. These findings would seem to add to the plausibility that at the onset of the first set of Bpress in the TS protocol the musculature predominantly involved in the Bpress exercise was not in a fatigued state-or, at least, in no more of a fatigued state than if a single set of 4RM Bpull had been performed 2 minutes prior to the onset of the Bpress. The performance of 3 sets of Bpull prior to the onset of 3 sets of Bpress had little effect on the outcome of the Bpress sets. If this is the case, it would seem that in a training session involving agonist/antagonist muscle groups, whereby agonist work is followed by antagonist work, in which volume maintenance is a desired outcome, RI between sets of both the first and second exercises should be similar. With respect to volume maintenance, given the results of the present study, consideration of antagonist work performed prior to agonist work is perhaps unwarranted.
Outcomes in acute efficiency (VL/time) do not necessarily translate into similar outcomes in chronic adaptation. That PS training is an efficient training method as compared to TS training does not necessarily mean PS training is efficient with respect to chronic adaptation. The training-induced outcome is affected by fatigue, the variable largely responsible for determining acute efficiency. It has been suggested that fatigue may, in fact, act as a stimulus for strength development (19). Ultimately, it is the training outcome that is of importance, and therefore fatigue (as reflected in a diminished ability to perform work) may or may not be detrimental or beneficial.
PS-type training has been prescribed for years by practitioners as a time-effective means of developing strength. However, scientific data to support its efficacy are limited. The current data indicate that heavy resistance (4RM) PS training allows a similar loading to be imposed on the musculature as that achieved with TS training. However, under both the PS and TS conditions VL was not maintained from set to set, suggesting that practitioners aiming to maintain VL may wish to implement RI of greater than 4 minutes when using heavy loads. Further research is required to determine the rest interval necessary for complete recovery when using heavy loads over multiple sets. Predictions as to the chronic effects of PS training would seem premature at this time. However, it is possible that PS training is an efficient, and effective, method of developing strength. If this is the case and practitioners are able to develop strength in a time-efficient manner, more time can be spent on other aspects of athletic development (e.g., skill development). Better use of resources (i.e., time) should theoretically result in the attainment of higher levels of athletic performance. Furthermore, because resistance training has been associated with improved health and a decrease in the risk of chronic disease and disability (24), time-efficient programs would likely have a positive effect on the health of the general population. Practitioners able to offer clients results in less time would likely see an increase in the number of individuals willing to adhere to resistance training programs. More people involved in resistance training would undoubtedly be a benefit in terms of overall population health. Given this possibility, longitudinal studies investigating the chronic effects of PS training are warranted.
This research was funded by the University of Ballarat (Australia). The authors would also like to thank the University of Victoria (Canada) and Canadian Sport Centre-Pacific for the allowance of laboratory space and equipment.
The authors have no conflicts of interest that are directly relevant to the contents of this manuscript.
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Keywords:© 2010 National Strength and Conditioning Association
paired set; bench press; bench pull; complex training