Resistance training, known as strength or weight training is a modality of exercise that has grown in popularity over the past two decades and has been recommended by many major health organizations 1 . The key factor of successful resistance training at any level of fitness or age is the appropriate program design 1 . American College of Sports Medicine (ACSM) 2 has indicated the main variables to acute program for resistance training: exercise choice, number of sets, resistance used, rest period length, and the order of exercise. Although most of these variables have been extensively studied over the past 2 decades 3–5 , exercise order has been studied less frequently in scientifically controlled investigations 4 .

It has been indicated that the exercise order is an important variable which affect both acute responses and chronic adaptations to resistance training programs and this may have a vital impact on the quality of the constituent exercise performed within a training session 4–7 . Traditional exercise order recommends that large muscle group or multi joint exercises generally is performed before small muscle group or single joint exercises, because this exercise order may result in the greatest long-term strength gains 1–7 .

Sforzo and Touey 7 reported that applying small muscle group exercises before large muscle group in trained men, resulted in significantly less total force production (repetitions × resistance) in training session. Speculation based on these findings suggested that, the large muscle groups, should be requested, before the small muscle group, in a training situation because it may be necessary for optimal strength gains 7 .

Few studies 8–10 have examined the influence of exercise order on the number of repetition and rating of perceived exertion (RPE) when the repetitions are performed until voluntary exhaustion. These studies demonstrated that performing both large and small muscle groups at the end of a training session resulted in significantly fewer repetitions or less strength gains compared to the same time when exercise was performed earlier in a workout sequence. It is usually recommended that the major goal exercises should be placed first in a training session in order to perform these exercises with maximal intensity. However, they did not find any significant difference in the rating of perceived exertion (RPE) between two different exercise orders (large to small, small to large), suggesting that exercise order does not influence the sense of effort at the end of the session 8–10 . Additionally, to our knowledge, no study has investigated the effect of exercise order with an intensity of 70% 1RM on the number of repetitions and RPE in lower-body muscles in untrained men.

Serum Creatine Kinase (CK) and lactate concentrations have been used as indicators of muscle damage after resistance exercise and may indicate the status of the muscle cell membranes 11–14 . Previous acute studies 11–13 , indicated that highly fatiguing resistance exercise protocols, that involve moderate intensity sets, performed with full repetition maximums (i.e., voluntary exhaustion) may induce significant microtrauma to muscle fibers. To our knowledge, the effect of the exercise order with moderate intensity on muscle performance is unclear. Therefore, the purpose of the present study was to compare the effect of acute bouts of resistance exercise order on the number of repetitions, RPE and muscle damage indices in untrained men.

CK levels in order A increased significantly 24 hours post the exercise (P < 0.05). Also, CK levels remained high at 48 hours post exercise (P < 0.05). A similar pattern was observed for CK in order B. There were no significant differences between corresponding CK values of two orders (P > 0.05) (Fig. 1). Differences in lactate concentrations for order A and order B are presented in Fig. 2. Within order A and order B, significant differences in lactate concentrations were demonstrated between pre and immediately post exercise sessions (P < 0.05). When the lactate concentrations were compared between order A and order B, no significant differences were demonstrated at immediately post exercise (P > 0.05). The comparison of sets between order A and the corresponding order B sets presented differences for 4 sets of HS (P < 0.05) and LC (P < 0.05). The LP and LE presented no significant difference between orders (P > 0.05) (Table 2). In relation to the total average of repetitions developed in each exercise per orders, differences were observed in HS exercise and LC (Fig. 3). There were no differences in the average of total number of exercise repetition for both resistance exercise orders (order A = 8 ± 1.61, order B = 8.78 ± 1.96). With regard to the OMNI scales, no differences were identified between order A (median = 8) and order B (median = 8). Increases in RPE for HS (order A: 8 and order B: 9) and LC (order A: 9 and order B: 8) were observed when those were performed later in the sequences (Table 3).

Fig. 1.

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Plasma CK concentrations order A and order B at before, 24 h and 48 h post exercise. Values are mean ± SD.* Significance difference to before test.

Fig. 2.

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Blood lactate concentrations order A and order B. Values are mean ± SD.* Significance difference to pre test (P < 0.05).

Fig. 3.

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Mean number of repetitions per exercise in both exercise orders. Values are mean ± SD. HS, hack squat; LP, leg press; LE, leg extension; LC, leg curl*. Significance difference found when compared to order A.

This study examined the effects of different resistance exercise orders on markers of muscle damage (CK, lactate), number of repetitions and rating perceived exertion (RPE) in the untrained men. One of the primary findings of this study was that CK and lactate concentration increase as a result of resistance exercise, regardless of exercise order. According to these findings, Bellezza et al. 15 have reported that there were no significant differences in lactate production in response to resistance exercise order in untrained men. These authors also reported that the average of total number of repetitions was greater from small to large condition 12 . Our study showed no significant difference in the average total number of repetitions between large to small (8.24 ± 1.35) and small to large (8.96 ± 1.48) conditions. It appears that the difference in the study of Bellezza et al. 15 is because the subjects did not perform full repetition maximum sets (10RM), on the contrary, in our study, all sets were performed with full repetition maximums until reaching a volitional fatigue for both exercise orders.

Similar to previous studies in which each exercise of the orders was performed to concentric failure in all sets 5,10 , the present study indicated that exercise order does affect the number of repetitions to volitional fatigue in small muscle group (single-joint) and large muscle group (multi-joint) when they precede exercise for the same general body part. For example, in a multi-joint exercise, the HS total mean number of repetitions decreased (33.6%) in order B when it was preceded by the LC, LE, and LP exercises. Similarly, the total mean number of repetitions performed in a single- joint exercise (LC) decreased (42.3%) in order A when it was preceded by the HS, LP, and LE exercises (Fig. 3). The pattern of a significant decrease in the total mean number of repetitions in four sets indicated that multi-joint and single-joint exercises performance were negatively impacted when performed later in sequence. This decrease in the number of repetition may be as the result of increasing fatigue as the exercise session progresses.

Simao et al. 15 examined the effect of exercise order on the total repetition performance in trained women. The exercise sessions consisted of three sets of each exercise with 80% of 1RM, with 2 min rest intervals between sets and exercises. One of the training sessions began with large muscle group exercise and progressed to exercises that involved small muscle groups (i.e. bench press, shoulder press, triceps extension, LP, LE, LC), while the other session progressed in the opposite order and lower body exercises being performed first in both sessions. Figueiredo et al. 10 compared the effect of exercise order on local muscular endurance (the number of repetitions) in trained women. Two exercise sessions consisted of four sets for each five exercises with 60% 1RM. 2 min rest were applied between sets and exercises. The exercise sequence utilized was bench press, lat pull down, shoulder press, biceps curl and triceps extension in one session, and the exact opposite order in the second exercise sessions (triceps extension, biceps curl, shoulder press, lat pull down and bench press). The results of both studies 5,10 indicated significantly fewer total repetitions for exercises performed later in the sequence, regardless of whether the exercise involved relatively large or small muscle group. These authors suggested that exercise is considered of primary importance to meet individual needs and movement patterns, and then it should be performed early in training session. Our study differs from the two mentioned studies in which the researcher 5,10 did not separate the effect of exercise orders on muscle damage indices. They analyzed only the effect of exercise order on the number of repetitions and RPE. However, there are 3 methodological differences between the present study and the above mentioned studies: (a) resistance utilized, (b) the subject population (men vs. women), (c) fitness level (untrained vs. trained). Despite these differences, the studies agree that when exercise for the same body part precedes another exercise of the same body part, performance decreased. Furthermore, our data demonstrated no significant changes for middle exercises of each sequence (i.e. LP, LE) and number of repetitions in the fourth set of each exercise within each order (Table 2).

Recent evidence suggests that OMNI scales provide a conveniently subjective estimate of resistance exercise intensity which can be used reliably to determine RPE 17–19 . These scales have also been used to evaluate the level of local fatigue or strain and/or discomfort during the resistance exercise session 17–19 . The 2 min rest interval may emphasize anaerobic glycolysis to a greater extent of the lactate production that is associated with the accumulation of H+ that lowers the pH of intracellular fluid 12 . The resulting effect is the afferent feedback from muscle chemoreceptors and nociceptors that associates with an increase in the perception of exertion. The central nervous system responds to the increase in RPE by increasing pulmonary ventilation and motor unit recruitment 19 . Therefore, we chose to use this scale at the end of each exercise in the orders as a measure of localized muscle fatigue. Our data indicated significant increases in the RPE median after the performance of four sets of HS (order B) and LC (order A) when this exercises were performed later in the orders. These increases are probably to the increased accumulation of H+ at the end of training session. In support of the RPE results, the current study also demonstrated a significant increase in blood lactate immediately after exercise session. In addition, significant differences were not found in perceived exertion scale between training orders, an observation which is confirmed by previous studies 4–10 . The significant difference in RPE scales happens just when a submaximal effort is done at a predetermined percentage of 1RM 17 . Therefore, in the present study we can conclude that the lack of significant difference in RPE between exercise orders may be due to the fact that each exercise of the orders was performed in voluntary exhaustion in all sets. Based on our knowledge, the present study is the first one that compares training intensity and muscle damage parameters in response to the two different exercise orders in lower body at untrained men. In the present study the training intensity of 70% 1RM has been utilized, which has not been used at this level in the previous studies 4–10 . The training intensity used in this study would be deemed by many to be of moderate intensity 15 . Therefore, this training intensity can provide health benefits for our sample, which consisted of college-aged men who were physically active and recreationally fit. Future studies are needed to compare the influence of exercise orders with higher-intensity on muscle damage biomarkers and training intensity parameter in lower and upper body exercises, as well as the effect of exercise order on oxidative damage markers. The results of the current study indicate that muscle damage, as indicated by CK and lactate concentrations and RPE was almost the same when resistance exercise orders were performed to voluntary exhaustion in untrained men with 70% 1RM. In addition, this study showed that in both, large and small muscle group exercises, the maximum number of repetitions performed in the last exercise of the order decreases in lower- body exercises.

The present study found that, the evaluation muscle damage biomarkers and RPE, in response to acute resistance exercise in lower-body, was independent of the order of exercise. If the purpose is to induce greater strength and hypertrophy, the exercises or movements most important to the objective of the training session should be performed at the beginning of the session.

The authors declare to have no conflict of interest.