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Original Research
Acute Effects of Different Set Configurations on Neuromuscular, Metabolic,
and Perceptual Responses in Young Women
FRANCISCO DALTON-ALVES†1, LÍGIA MARTINS*2, WITALO KASSIANO†3, MÁRIO
SIMIM‡4, ALEXANDRE I. A. MEDEIROS‡4, and CLÁUDIO DE O. ASSUMPÇÃO‡5
1Biotechnology and Exercise Biology Research Laboratory, Institute of Physical Education and
Sports, Federal University of Ceará, Fortaleza, CE, BRAZIL; 2Department of Physiology and
Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, BRAZIL;
3GEPEMENE—Metabolism, Nutrition, and Exercise Laboratory, Londrina State University,
Londrina, PR, BRAZIL; 4Biodynamics Research Group of Human Movement, Institute of
Physical Education and Sports, Federal University of Ceará, Fortaleza, CE, BRAZIL; 5Applied
Physiology, Nutrition, and Exercise Research Group, Exercise Biology Research Lab,
Department of Sport Sciences, Health Science Institute, Federal University of Triangulo Mineiro,
Uberaba, BRAZIL
*Denotes undergraduate student author, †Denotes graduate student author, ‡Denotes professional author
ABSTRACT
International Journal of Exercise Science 16(4): 974-986, 2023. We compared neuromuscular, metabolic,
and perceptual responses between different resistance training configurations in young women. In a
counterbalanced randomized order, 13 young women performed the following protocols in separate sessions (sets
x repetitions): traditional (TRAD): 5x10, 90-s of rest interval between sets; more frequent and shorter total rest (FSR):
10x5, 30-s of rest interval between sets. The sessions were composed of leg press exercise with the same intensity.
Force (maximum voluntary isometric contraction [MVIC]) and metabolic (lactate concentration) responses were
measured pre- and post-resistance training sessions. The rating of perceived exertion (RPE) was measured after
each set. The internal training load was calculated using the session-RPE method. There was a significant reduction
in the MVIC only after TRAD configuration (Effect size [ES] = 0.36). The lactate concentration increased in both
conditions but was higher after TRAD (ES = 2.81) than FSR (ES = 1.23). The RPE has progressively increased in both
configurations. On the other hand, the internal training load was lower in the FSR configuration. From our findings,
we suggest that more frequent and shorter total rest is an effective strategy for maintaining the ability to produce
force, generating less metabolic stress and lower perceived internal load in young women.
KEY WORDS: Strength training, cluster set, intra-set rest, force, fatigability, neuromuscular
function
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INTRODUCTION
Resistance training (RT) promotes gains in muscle mass and strength (1). These adaptations
allow—among other benefits—to improve neuromuscular performance (1). In this sense,
researchers and strength and conditioning professionals manipulate different variables, such as
intensity, volume, and rest interval, in order to promote positive adaptations with the minimum
of fatigue and in the most efficient way possible (11, 15). In this regard, some set configurations
that have become popular are the use of cluster sets and rest redistribution (11, 15). Among the
different ways to apply such techniques, the use of inter-repetition and intra-set rest intervals
has been effective in allowing the practitioner to train at the same relative intensity (or higher)
and volume as the traditional configuration, with the benefit of mitigating residual
neuromuscular fatigue and hemodynamic stress during and after the RT session (11, 12, 15).
In fact, in two recent systematic reviews with meta-analysis, the authors demonstrated that
different cluster configurations characterized by the inclusion of intra-set rest intervals are
effective strategies to reduce fatigue, metabolic stress, and perceptual effort during and after
training sessions (11, 15). Importantly, such configurations commonly have similar or greater
total rest compared to the traditional protocol (11, 13, 15). Therefore, less is known about
whether allowing more frequent recovery in parallel with a shorter total rest time would still
confer such advantages in comparison to traditional configuration. This aspect is important,
because if such advantages are observed even with a lower total rest time when compared to
traditional configuration, this can reduce the total time of the session, making it more efficient
and potentially more attractive to practitioners who have less time to train.
Another important aspect frequently sought by researchers and coaches concerns the interplay
between internal and external load parameters (19). In this sense, Marston, et al. (18) observed
that the session density was able to discriminate sessions with characteristics for the
development of strength versus hypertrophy. Namely, the greater the density of the session, the
greater the metabolic stress (18). From this, the authors proposed that this external load metric
would provide an accurate representation of the interplay between the work performed and the
acute internal responses (18). Notwithstanding, the implementation of more frequent rest
intervals can modify the acute changes, even in response to two protocols with similar intensity
and volume (11, 19). Therefore, it remains to be determined how the inclusion of more frequent
intervals and shorter total rest might affect the interplay between internal and external load
parameters.
Moreover, a current limitation on this matter is the underrepresentation of women in studies of
exercise science. Indeed, when looking more closely at the state of the art regarding set
configurations and acute responses, we noticed that a small proportion of the investigations
included young women; for example, in the most recent review (11), of the 27 included studies,
four were composed of a mixed sample and only one was carried out exclusively with women.
Since there is relevant sexual dimorphism in physiological (eg., sex differences in fatigability)
responses to exercise (9, 10), this underrepresentation may result in inadequate extrapolation of
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these results in response to manipulation of the set configuration in women (9, 10, 21). These
data highlight the importance of greater inclusion of female participants to guide the
prescription of RT for this population, taking into account evidence obtained in young women.
Therefore, given the scenario described above, the present study had as main objectives: (a) to
test whether there are differences in neuromuscular, metabolic, and perceptual alterations in
response to traditional and more frequent and shorter total rest configurations with similar
intensity and volume in young women; in addition, (b) verify whether the metabolic changes
are related to external and internal load metrics.
METHODS
Participants
We estimated the sample size using G*Power (version 3.1.9.6). Previous data on the effects of
resistance exercise on neuromuscular performance were used to estimate the sample size (13).
Thus, we estimated the required sample based on an effect size of 0.63, a significance level of
0.05, and a power of 0.80. The analysis indicated that at least 10 participants were needed to
achieve adequate statistical power. Thirteen young women participated in this study (23.3 ± 3.7
years old, 1.61 ± 0.5 m, 58.8 ± 7.6 kg, body fat = 21.5 ± 4.5%). Potential participants were contacted
through digital media (e.g., Facebook, Instagram) and personal invitations. As inclusion criteria,
a) the participants should have at least six months of practice in the RT; b) who had the 45° leg
press exercise in their RT routines; c) not answering “yes” to any of the questions present in the
physical fitness readiness questionnaire (Physical Activity Readiness Questionnaire—PAR-Q);
d) not have any myoarticular limitations that would limit the participants to carry out the
experimental procedures, and; e) not using any ergogenic substances that improves
performance or delay neuromuscular fatigue. A detailed description was made for each
participant about all the procedures of our study and then they signed the free and informed
consent form. The participants were instructed to avoid resistance exercise 48 h before the visits
for tests and experimental sessions and to maintain their eating habits. This investigation was
performed according to the Declaration of Helsinki and was approved by the local University
Ethics Committee (2.266.738). The investigation meets the guidelines set forth by the
International Journal of Exercise Science (22). All procedures described below were performed
between 6 AM and 10 AM, to avoid possible effects of the circadian cycle.
Protocol
We conducted a crossover, counterbalanced, and randomized study to investigate the acute
effects of two different set configurations on neuromuscular, metabolic, and perceptual
responses in young women. The total duration of the study was 4 weeks. Weeks 1 and 2 were
used for anthropometry measurements and repetitions maximum (RM) testing. Weeks 3 and 4
were used for the application of the experimental training sessions. During that period, each
participant visited the laboratory on five occasions to perform the procedures and experimental
sessions. Visit one consisted of anthropometric assessment, body composition, and
familiarization of the participants with the procedures and equipment. Visits two and three,
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which took place 48 hours after the first visit, participants performed test and retest of 10
repetitions maximum (10RM) in 45° leg press to determine the load to be used in the
experimental sessions. In visits four and five, which took place 72 hours after the third visit,
participants performed the experimental sessions composed of 45° leg press exercise, namely:
traditional configuration (TRAD) and more frequent and shorter total rest (FSR) (Figure 1).
Participants were asked to avoid exercise or sporting activity 72 hours before each laboratory
visit.
Figure 1. Experimental design. TQR = total quality recovery; MVIC = maximum voluntary isometric contraction;
TRAD = traditional configuration; FSR = frequent and shorter total rest.
Total quality recovery: The total quality recovery (TQR) scale (16) was used before both
experimental conditions to assess the level of perceived recovery. Upon arriving at the
laboratory, the participants were asked how well they were recovered. TQR is a scale that ranges
from zero (very poorly recovered/extremely tired), 1, 2, and 3 (not well recovered/somewhat
tired), 4 (somewhat recovered), 5 (adequately recovered), 6 (moderately recovered), 7, 8, 9 (well
recovered/somewhat energetic), and 10 (very well recovered/highly energetic) (16). A higher
level of perceived recovery is associated with higher values. Participants were familiarized with
this scale on visits two and three. The data collected in visits four, and five (days of the
experimental conditions) were used for the analyses.
Dynamic muscular strength: The determination of the load that was used in the experimental
sessions was made from the 10RM test. We adopted this number of repetitions because it is a
commonly prescribed intensity (5, 6). The 10RM test was performed in the 45° leg press exercise
and was repeated in two non-consecutive days — 48 h interval between sessions. The 45° leg
press was performed in a conventional free-weight machine. Initially, the participants were
taken to the laboratory at the beginning of the procedures, namely: a general warm-up was
performed on a cycle ergometer (Biotec 2100, Cefise, São Paulo, Brazil) lasting five minutes at
an intensity corresponding to 50% of the estimated maximum heart rate. After the general
warm-up, the participants performed a specific warm-up consisting of two sets of 10 repetitions
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spaced by one minute of rest; the first set was performed at approximately 50% of the estimated
10-repetition maximum (10RM), and the second set, at 70% of 10RM. Two minutes after the end
of the specific warm-up, attempts were made to find the 10RM. Each participant made five
attempts, with a five-minute rest interval. The weight adjustment between attempts in which
the participant performed more or less than 10 repetitions was ~3–5%. The range of motion
necessary to consider a repetition valid was when the knees and hip angles reached 90° and
110°, respectively, with proper technique (14). The adjustments made in the equipment to
accommodate the anthropometric characteristics of each participant were recorded and
repeated in both the 10RM testing sessions and in the experimental sessions. The tests were
monitored by the same evaluators. The mean and standard deviation of 10RM was 124.7 ± 48.3
kg. The reliability measures were obtained from the 10RM scores of the test and retest, and we
obtained the intraclass correlation coefficient of 0.99 (0.98–0.99).
Blood lactate concentration: We obtained the lactacidemia at pre — before the warm-up
procedures — and immediately after the end of both experimental RT sessions. The lactate
concentration was quantified from a blood sample of ~15 μl extracted from the participant’s
fingers. These samples were immediately inserted into lactate tape containing sodium fluoride
solution and inserted in the portable lactimeter (Accutrend® Plus, Roche, São Paulo, Brazil). The
lactate concentration result was indicated after one minute. The reliability parameters for this
device present a satisfactory coefficient of variation ranging between 1.8–3.3% for low, medium,
and high concentrations of lactate; and ICC = 0.99 (3).
Maximum voluntary isometric contraction (MVIC): The force was measured before and after
both experimental sessions by the maximum voluntary isometric contraction (MVIC). The tests
were performed in a leg press (isometric dynamometer, Cefise, São Paulo, Brazil) with an
attached load cell. The signal was captured with an analogic-to-digital converter using a
sampling frequency of 100 Hz and analyzed in a specific software (N2000 Pro, Cefise, São Paulo,
Brazil). The participants performed the MVIC with the knees and hip angles at 90° and 110°.
After completing the blood sample collection, the participants performed the same warm-up as
described in the 10RM test. After this stage, the pre-experiment MVIC measurement procedures
were started. Participants were placed in a seated position, adjusted based on the manufacturers’
recommendations in ~ 110º of hip flexion, according to the anatomical position. The feet were
placed on the leg press platform with shoulder-width spacing and the feet were slightly rotated
externally. The dynamometer was calibrated before all measurements according to the
manufacturer’s recommendations. The participants’ hands were kept at their sides, holding the
equipment handle. The measurement after the experimental conditions had a delay of ~120 s,
due to the time of displacement from the 45° leg press machine to the isometric dynamometer,
and to adjust the participants' position on the dynamometer. Each participant performed three
MVIC lasting 5 s and the rest of 30 s between each repetition. Participants were encouraged by
claps and words of incentive to apply as much effort as possible during the test. The highest
peak torque among the three trials was considered as MVIC and was expressed in Nm. The
assessments were performed by the same evaluators. The reliability of the MVIC was calculated
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from the values obtained before the experimental conditions and obtained an ICC = 0.97 (0.90–
0.99).
Experimental protocols: The present investigation consisted of two experimental sessions in the
45° leg press exercise in a conventional free-weight machine with different configurations,
namely traditional (TRAD) and the more frequent and shorter rest (FSR) configurations.
Initially, the participant was taken to the laboratory for blood collection to measure lactate
before the exercise. Then the participant performed a general warm-up on the cycle ergometer
and a specific warm-up on 45° leg press exercise, identical to the procedures described in the
10RM test section. Two minutes after performing the specific warm-up, one of the two
experimental sessions. The TRAD configuration was characterized by five sets with the load
corresponding to 10RM and 90 s of rest interval between each set; totalizing 360 s. The FSR
configuration consisted of 10 sets of 5 repetitions with a 30 s rest interval between sets; totalizing
270 s. Muscle actions — concentric and eccentric — were performed for two seconds and were
monitored by a metronome. The sessions were accompanied by the same professionals, who
verbally encouraged the participants throughout the sets, as well as, when necessary, provided
assistance in the final repetitions so that the participants completed the predetermined number
of repetitions (ie., 50 repetitions) — mainly in the TRAD. The time under tension of each set was
quantified using a stopwatch and was used to calculate the time under tension of the session.
The volume-load was calculated from the multiplication of the number of repetitions x load and
is presented in kg. The session density was obtained from the volume-load (kg) divided by the
total rest interval in seconds (14, 18). A washout period of seven days was given between
experimental sessions to avoid possible effects of residual fatigue.
Rating of perceived exertion (RPE) and internal training load: The OMNI-RES scale (23) was
used to obtain the RPE from the experimental sessions. All participants were submitted to two
sessions (visits two and three) for the RPE anchoring procedures. Participants were asked to
indicate a score corresponding to perceived exertion experienced during the resistance exercise
sessions in visits four, and five. The RPE was obtained after the end of each set in both
experimental conditions, through the following question: “How hard was this set of
repetitions?”. The RPE of the session was obtained by the average of the RPE of each set. The
internal training load was obtained from the session-RPE method using the following equation:
RPE x duration of the session in seconds (20).
Statistical analysis
The normality of the data was tested using the Shapiro-Wilk. The variables TQR, density, time
under tension, duration of the session, RPE, and internal training load were compared using the
paired t-test. For the primary study aim, we conducted a repeated-measures analysis of variance
(ANOVA) with the condition (TRAD vs. FSR) and time (pre vs. post) as fixed factors. When the
F was significant, a Bonferroni (Bonf) posthoc test was used to identify possible statistical
differences. The Cohen’s effect size (ES) was calculated as post- mean minus pre-values mean,
divided by pooled pre-values standard deviation (4). The ES values were interpreted as follows:
≤ 0.20 was considered small, > 0.20 to < 0.80 was considered medium, and ≥ 0.80 was considered
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large (24). For the second aim, we used coefficient Pearson's correlation coefficient (r) for testing
the potential relationship between the changes (Δ%) of lactate from pre- to post-session and
density and internal training load. The r values were interpreted as follows: 0.00-0.19 was
interpreted as no correlation, 0.20-0.39 was interpreted as low correlation, 0.40-0.59 was
interpreted as moderate correlation, 0.60-0.79 was interpreted as moderately high correlation,
and ≥ 0.80 was interpreted as high correlation (24). The data were presented in mean, standard
deviation, and 95% confidence interval. The accepted level of significance was < 0.05. The data
were analyzed using the JASP software (version 0.11.1, Amsterdam, NL).
RESULTS
Table 1 shows the mean and standard deviation values for perceptual and performance
measures. There was no difference in the state of recovery before the start of the two
experimental conditions. The number of total repetitions and volume-load were the same:
repetitions = 50.0 ± 0.0, and volume-load = 6515.3 ± 2430.3. The session density was higher in
the FSR condition, with no significant differences for time under tension. The total duration of
the session was shorter in the FSR condition. There was no difference in RPE, on the other hand,
the internal training load was significantly lower in the FSR condition.
Table 1. Performance and perceptual outcomes in both experimental conditions.
Variables
Conditions
P
ES
TRAD
FSR
TQR (AU)
7.2 ± 2.1
6.9 ± 2.1
0.447
0.22
Density (kg . s -1)
18.1 ± 6.7
24.1 ± 8.9
< 0.001
2.67
Time under tension (s)
196.6 ± 14.7
205.5 ± 12.9
0.159
0.43
Duration of session (s)
556.3 ± 14.7
475.5 ± 12.9
< 0.001
4.59
mean-RPE (AU)
7.4 ± 1.1
7.0 ± 1.7
0.314
0.30
Internal training load (AU)
4133.1 ± 647.0
3362.2 ± 878.1
0.005
1.00
Notes. TRAD = traditional configuration; FSR = frequent and shorter rest configuration; ES = effect size; TQR =
total quality recovery; AU = arbitrary units.
With regard to RPE during the experimental sessions, there was a significant effect of time (F4, 1
= 61.801, P < 0.001), with no effect of interaction time (F4, 1 = 0.238, P = 0.916) and condition time
(F4, 1 = 1.114, P = 0.314). More precisely, the RPE increased from the 10th repetition, stabilized
until the 30th repetition, and increased again at the 40th repetition in both experimental
conditions (Figure 2).
The values of mean, standard deviation, confidence interval, and ES for MVIC and lactate are
described in Table 2; individual behavior is shown in Figure 3.
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Figure 2. Perceptual behavior in response to TRAD and FSR configurations. TRAD = traditional configuration; FSR
= frequent and shorter total rest; RPE = rating of perceived exertion; AU = arbitrary units. a = P < 0.05 vs. at 10th
repetition; b = P < 0.05 vs. at 20th repetition.
Table 2. Neuromuscular and metabolic responses in TRAD and FSR configurations.
TRAD
FSR
MVIC (Nm)
Pre
155.9 ± 49.2
152.4 ± 51.0
Post
139.6 ± 38.7*
143.8 ± 48.8
∆ (95% CI)
-16.3 (-31.4; -1.2)
-8.6 (-6.4; 23.6)
ES
0.36
0.17
Lactate (mmol/L)
Pre
3.84 ± 1.01
4.37 ± 1.42
Post
9.09 ± 2.44*
5.93 ± 1.13*†
∆ (95% CI)
5.25 (3.36; 7.13)
1.55 (0.06; 3.05)
ES
2.81
1.23
Notes. TRAD = traditional configuration; FSR = frequent and shorter rest; MVIC = maximum voluntary
isometric; ES = effect size. * = P < 0.05 pre versus post; † = significant difference between configurations. Pre and
post data are presented as mean and standard deviation, whereas the mean difference (∆) as mean and
confidence interval.
Regarding force output, there was an effect of time (F1, 12 = 9.32, P = 0.012), with no effect of
interaction (F1, 12 = 1.56, P = 0.240) and condition (F1, 12 = 0.00, P = 0.948) for the MVIC. From the
post-hoc it was possible to observe that the MVIC reduced only in the TRAD condition (PBonf =
0.030), but no after the FSR (PBonf = 0.378) (Table 2 and Figure 3A).
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Figure 3. Neuromuscular and metabolic changes in response to the two set configurations. TRAD = traditional
configuration; FSR = frequent and shorter total rest; MVIC = maximum voluntary isometric contraction; * = P < 0.05
pre versus post; † = significant difference between configurations.
Regarding metabolic changes, there was an effect of interaction (F1, 12 = 7.847, P = 0.001) and time
(F1, 12 = 134.804, P < 0.001), and condition (F1, 12 = 4.935, P = 0.048). More precisely, there was an
increase in lactate concentration after both experimental conditions (Table 2 and Figure 3B), but
this increase was greater after TRAD (PBonf = 0.002).
There was no correlation between changes in the lactate concentration and density and low
correlation between changes in the lactate concentration and ITL (Figure 4).
Figure 4. Relationship between metabolic changes and external and internal metrics. ITL = internal training load.
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DISCUSSION
In the present study, we sought to test whether there are differences between two sets
configurations (TRAD vs. FSR) on neuromuscular, metabolic, and perceptual responses in
young women. In addition, we verify if the metabolic changes can be explained by external (ie.,
session density) and/or internal (ie., internal training load) load variables. Our main findings
were: (a) the FSR configuration was effective for maintaining the ability to produce force, and
induced lower metabolic stress and internal training load in young women; (b) the FSR
configuration allowed performing the exercise with the same relative intensity (10RM) and
volume-load in less time (ie., shorter session duration); (c) the RPE increased throughout the sets
and in a similar way between both experimental conditions; (d) we found no relationship
between metabolic changes, density and internal training load in young women.
The development of strength and power are among the main adaptations induced by RT (1). In
this sense, different strategies are being applied in order to optimize these adaptations with the
least fatigue (11, 15). Among them, the redistribution of rest within and between sets has become
increasingly popular for its effectiveness in maintaining neuromuscular performance during
and after a session (11). However, to the best of our knowledge, only one study (21) compared
the effects of different sets configurations on the neuromuscular performance of women. In this
study, Merrigan, et al. (21) observed that inserting 30 s of rest in the middle of the sets reduced
the velocity loss within sets when compared to the traditional protocol. In the present study, we
also observed that the FSR configuration did not reduce the force output after an RT session
with a high-volume protocol; on the other hand, after the TRAD condition, there was a reduction
in MVIC, even with both configurations being performed with the same intensity and volume.
Parallel to these findings on force output, we observed that the inclusion of 30 s in the middle
of each set, although it significantly increased the lactate concentration, this change occurred to
a lesser extent than after TRAD (see Table 2 and Figure 2). During high-volume training (eg.,
multiple high-repetition sets) anaerobic glycolysis is probably more prevalent, a fact that can
contribute to the accumulation of lactate, as well as other metabolites such as ammonia (7, 8).
Interestingly, the FSR configuration favored lower metabolic stress, even in response to a high-
volume protocol. These findings can be explained, in part, because of the inclusion of rest intra-
set that may have allowed the reestablishment of energy systems, more precisely the glycolytic
pathway, attenuating the depletion of ATP and PCr (2, 8). Although debatable, the lower
metabolic stress may have contributed to the maintenance of force output in the FSR
configuration (2, 8).
RPE increased progressively and similarly in both configurations until repetition 40, as well as
without significant differences. These findings are in accordance with a previous study carried
out with young women who were also submitted to sessions with five sets in the leg press but
with manipulation of the interval between sets (ie., 1 vs. 2. vs 3 min rest interval), in which there
was no difference in the RPE (14). These findings can be explained by indications that RPE
appears to be largely determined by central commands, and less by what occurs on the
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periphery (17). On the other hand, in the present study, we observed a greater internal training
load in response to TRAD configuration. Together, these findings indicate that the perceived
effort alone does not seem to be sensitive to discriminate between the two protocols, on the other
hand, when calculating the perceived internal load taking into account the work performed, the
FSR condition induces less perceived stress.
Regarding the possible interplay between internal and external load parameters, we seek to
verify whether the metric session density (volume-load divided by the total rest interval) and
internal training load (RPE x duration) would be related to the induced metabolic changes in RT
sessions; and we did not observe a significant relationship between these parameters. In contrast
to our findings, Marston, et al. (18) observed a significant correlation between changes in lactate
concentration and density (r = 0.66). Therefore, suggesting that this external load metric would
represent what happened to metabolic changes (18). A possible explanation for such divergence
between our study and Marston, et al. (18) may be in the configuration of the RT sessions. In the
present study, we compared protocols with the same intensity (10RM) and volume-load, while
(18) compared a protocol that prioritized strength (5RM) versus hypertrophy (10RM). Taken
together, such divergences in the findings shed light on the fact that perhaps a single metric —
be it internal or external load — is unlikely to accurately represent the effects of all possible set
configurations in an RT session.
To our knowledge, this is the first study that compared the effects of the TRAD versus FSR
protocol on neuromuscular, metabolic, and perceptual responses in young women. Our study
has strengths and weaknesses that deserve to be mentioned. We provide a representative picture
of the effects induced by the two sets configurations when presenting the behavior of
neuromuscular, metabolic, and perceptual parameters. However, we did not measure
mechanical parameters (eg., velocity during and after RT sessions). Another important
limitation is the fact that we did not time-course our dependent variables. Therefore, future
investigations may consider adding the measurement of mechanical parameters, as well as
monitoring the time course of the variables of interest. Furthermore, although we observed that
the TRAD configuration induced a reduction in force output, the effect size of the reduction was
medium, so further investigations should be conducted to identify whether this change is
replicated and what is the practical relevance of this magnitude of reduction in force output.
Finally, the RT sessions were composed of a single exercise. Since the RT sessions are composed
of more exercises, future studies that take this feature into account are necessary.
Conclusion: From a practical standpoint, our findings indicate that the insertion of more
frequent and shorter total rest is an effective strategy to maintain force output, as well as seems
to induce lower metabolic and perceived stress in young women. This seems to be possible even
when the participant is underwent a protocol with multiple high-repetition sets in a multi-joint
lower body exercise. Therefore, strength and conditioning professionals can consider the use of
a more frequent and shorter total rest in young women when the objective of the session is to
training with high-repetition volume without accumulation of fatigue and lower metabolic
stress after the RT session. In addition to these advantages, the adoption of this set configuration
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may allow shortening the total session duration. Besides, our findings highlight the need to
monitor different internal and external load parameters, to obtain an accurate picture of what
happened during and after the session; because a single variable (eg., density and internal
training load) does not seem to be enough to represent the complex interplay between internal
and external loads.
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