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DEVELOPMENT OF PREDICTION MODELS TO ESTIMATE 1-RM FOR UPPER AND
LOWER BODY EXERCISES IN NON -RESISTANCE TRAINED WOMEN
SUBMITTED BY :- SADASHIV HANCHINAL
ABSTRACT
The objective of the present study was to build up a condition for foreseeing the workload of one maximal
redundancy (1RM) in wom-en and men, construct only in light of anthropometrical characteris-tics.
Forty-four generally safe and experienced in quality preparing youthful subjects, being 22 male (23 ± 4
years, 76.6 ± 12.7 kg, 173.9 ± 5.5 cm, 11 ± 4.5% of muscle to fat quotients) and 22 female (22 ± 4 years,
54 ± 6.0 kg, 161 ± 5.8 cm, 18 ± 2.2% of muscle to fat ratio ratios) volunteered for this study. All subjects
were submitted to an anthropometrical assessment fol-lowed by a 1RM acclimation test (shoulder press),
which was rehashed after 48 h. The repeatability was tried utilizing Wilcoxon Matched combined test. At
long last, the 1RM workload was displayed in connection to the anthropometrical variables through
numerous straight relapse (forward stepwise) utilizing as cutoff criteria for the inde-pendent variables ∆r
2 < 0.01. The models unwavering quality was communicated by the Bland and Altman investigation. All
tests expected α = 0.05. No critical contrasts were recorded between the two tests, re-sulting 44.6 ± 13.2
kg and 12.2 ± 3.2 kg, for male (MS) and female (FS) subjects separately. The season of practice in quality
preparing was likewise incorporated into the models. The model brought about 84% of clarified
difference and a standard mistake of 12% for the MS. Then again, for the FS the prescient limit was
weaker than for = the MS, bringing about 56% of the clarified change and a stan-dard mistake of 20%.
Taking everything into account, the acquired models indicated adequate dependability with the goal that
they can be as of now utilized as an instrument for foreseeing the 1RM workload. workload only taking
into account male and female anthropometric characteris-tics.
INTRODUCTION
The one maximal reiteration test (1RM) is every now and again utilized as estimation of solid quality in
physical readiness, sports preparing, physical recovery or basically in the experimental exploration
perspective. Inside this setting, it is an agreement that the ground-ing for the activity remedy in counterresistance preparing (CRT) is set up through the connection between the 1RM rate and the quantity of
repetitions(1). Then again, past stud-ies have demonstrated that few components –, for example, physical
condition-ing level(2); solid group(3); rest routine(4); diet(5); chronobiologi-cal rhythm(6);
motivation(7); menstrual cycle(8) and strong fatigue(9) – successfully meddle in such connection,
bringing about particular intense-ties for a given number of reiterations.Furthermore, long time required
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for the execution of a 1RM test, strong discomfort(10), and conceivable dangers of injury(11), have
decided the advancement of more straightforward and less damage inclined techniques which are still
prepared to do precisely evaluating the maximal quality. Subsequently, with the reason to foresee the
maximal quality without maximal physical and passionate anxiety, a few studies have utilized the
acceptance of submaximal tests taking into account the maximal number of redundancies for each
workload(12-13); on the 1RM percentage(4,15); on the maximal workload for a given number of
repetitions(16-20), or basically on anthropometric attributes, for example, stature, segmental region, solid
area(21-26), or body mass(10,27). On the other hand, despite the fact that the writing is rich in work
including the 1RM evaluation, few studies have concentrated on anthropometric character-istics of the
Brazilian populace. In this manner, the point of the present study was to build up a model for foreseeing
the 1RM.
METHODS
Experimental procedures
Forty-four volunteers (22 male and 22 female) randomly select-ed in a health club of Rio de Janeiro
participated in this study. The inclusion criteria considered were: that the volunteers had at least six
months of experience in CRT; that they did not use any ergo-genic device and that they did not present
any previous osteomio-articular injury. These were considered low risk individuals since they presented
up to a risk factor for arterial coronary disease and did not present any sign or symptom suggestive of
cardiopulmo-nary or metabolic disease. All volunteers were previously instructed not to perform physical exercise in the 24 h prior to the tests, not to ingest alcoholic beverages and to remain hydrated
throughout the tests. The ex-perimental procedures took place only after the verbal consent and the
signature of the free and clarified form, according to the Re-search Ethics Committee of the Estácio de Sá
University. The vol-unteers were initially submitted to an anthropometric evaluation followed by a
familiarization 1RM test(28), and in a 48 h minimum interval, 1RM retest was performed. All 1RM tests
were performed between 5:00 and 7:00 p.m.
Anthropometric evaluation
It consisted of body mass (BM) and height measurement (H), performed with a mechanical scale with
stadiometers (Filizola, Bra-zil). For the calculation of the area of the transversal section of the segment, it
was necessary to measure the circumference of the right arm relaxed (AC) as a standard using an
anthropometric tape (Sanny, Brazil), as well as the skinfold (S) of the brachial triceps with scientific
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dividers (Cescorf, Brazil). From these measurements, the fat percentage (F) and the fat-free mass (FFM)
were calculated using the Jackson and Pollock equations(29), Jackson et al.(30) for the estimation of the
body density on men and women, respec-tively, combined with the Siri’s equation(31). From the SC
measurement, the arm transversal area section was calculated (As The advancement exercise on the
machine was chosen due to its multi-articular nature, other than offering low harm hazard. In addition, in
spite of the fact that there are a few studies managing activities, for example, recumbent, leg press and
seat press among others, until the present study there is no register of results managing the 1RM workload forecast for this sort of activity. The test began from the introductory situated position with back
against the seat, flexed knees with feet on the seat, flexed elbows, snatched shoulders and bar grasp
moderately more extensive than the shoulders adjusting. In the concen- tric stage, the shoulders
kidnapping and elbows augmentation were at the same time performed from the underlying position, and
successive ly, the unusual stage comprised of the arrival to the underlying posi- tion. The 1RM tests were
led by convention master postured by Brown and Weir(28): 3-5 min of light action which in- volved the
tried strong gathering were performed; following one moment of light extending, warming-up of eight
redundancies at half of per- ceived 1RM, trailed by three redundancies at 70% of saw 1RM. After 5 min
interim, the 1RM test was performed, including whenever required, 0.4 to 5 Kg, with a sum of 3 to 5
trials. The regis-tered maximal workload was that one lifted in a solitary development. Where BM speaks
to body mass; FFM without fat mass; RF relative fat; AC loose arm circumfer-ence; experience time in
counter-resistance preparing; AS arm segmental zone; MA arm strong region; and FA arm fat range.
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Where BM represents body mass; FFM fat-free mass; RF relative fat; AC relaxed arm circumference;
Experience experience time in counter-resistance training; AS arm segmental area; MA arm muscular
area; and FA arm fat area.
Where Ntrial test is the number of trials in the test and Ntrial retest is the number of trials in the retest.
Measurable treatment
The 1RM test repeatability was affirmed by the non-paramet-ric test of requested sets by Wilcoxon. The
1RM workload was mod-eled by numerous direct relapse through quadratic blunder minimi-zation
(forward stepwise strategy), utilizing as free variables:
age; H; BM; FFM; RF; SC; SA; MA and FA, other than the experience time in quality preparing. A
variety in the r2 littler than 0.01, as well as its – p worth was embraced as cutting criteria of the indepenimprint variables. The relapse models unwavering quality was communicated by the appraisal standard
mistake (SEE) and concentrated on through the strategy by Bland and Altman(32), in which the deliberate
estimation of the 1RM workload was connected in the even pivot, and the distinction between the
deliberate qualities and those acquired by the technique in the vertical pivot. What's more, 95% of the
farthest point of assention (LOA) was exhibited, being communicated as the interim between two standard deviations (± 2SD). In every single connected test, α = 0,05 was received. Every single factual
strategy were performed in Matlab v6.2 (Math- works, EUA).
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Where FFM is fat-free mass; RG is relative fat; AC is arm circumference; experience is experience time
in counter-resistance training; AS is segmental area; MA is muscular area and FA is fat area.
RESULTS
No osteomioarticular issue was enlisted amid or immedi-ately after any test; along these lines, all
volunteers have achieved the maximal workload in the 1RM tests in the improvement exercise. In table 1
the physical and anthropometric qualities are pre-sented, and also the experience time in CRT of the
volunteers. As one can see, aside from the experience time – which shifted from 6 months to 5 years – the
information low scattering focuses to a test amass genuinely homogeneous. In table 2 the 1RM workloads
and the quantity of trials acquired in the test and retest of 1RM of the volunteers are displayed. In spite of
the fact that the 1RM workload got in the retest is averagely higher than the one in the acquaintance test,
no critical contrast ences were enlisted, which prompted a high relationship between'sphrasing of the
1RM workload.
Table 3 introduces the coefficients of fractional connection between's the anthropometric variables
(autonomous) and the 1RM workload (subordinate variable). The involvement in CRT brought about
31% of the difference clarified of the 1RM workload. Additionally, the an- thropometric variables gave
the most elevated relationships the 1RM workload in the SM. The BM contributed with 28% (p = 0.01)
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and the FFM with 31% (p < 0.01); regardless, the most elevated relationships were gotten by the SC and
the AS (r2 = 0.73, p < 0.01). In the SF, the relationships were lower, achieving determina-tion coefficients
of 0.23 (age) and 0.18 FFM (p<0.05). Table 4 outlines the expectation models of 1RM utilizing from two
to six free variables. All separated models were signif-icant; in any case, it is conceivable to notice that,
despite the fact that there is a propensity to expand the clarification coefficient as the indepen-tch
variables are included, the SEE has a tendency to be steady, which appears that no information is added to
the prediction capacity of the mod-els. Therefore, the best model for the estimation of 1RM was giv-en to
the equation which presented the highest determination co-efficient and lowest standard error of the
statistics. The models resulted in r2 = 0.84 with error equivalent to 12% (SEE = 5.94 kg, p < 0.001) in the
SM. In the SF though, the predictive capacity of the model obtained was weaker, resulting in r 2 = 0.56
and stan-dard error of 20% (SEE = 2.52 kg, p < 0.05).
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The models resulted in r2 = 0.84 with error equivalent to 12% (SEE = 5.94 kg, p < 0.001) in the SM. In
the SF though, the predictive capacity of the model obtained was weaker, resulting in r 2 = 0.56 and standard error of 20% (SEE = 2.52 kg, p < 0.05). The reliability of the regression models was studied through
the Bland and Altman method(32), in which the measured 1RM work-load was applied on the horizontal
axis and the difference between the measured values and those obtained by the model were ap-plied on
the vertical axis. Figure 1 illustrates the ratio between the measured and expected 1RM values in both
sexes, as well as the Bland and Altman analysis. The obtained models showed reliability of 95% of the
limit of agreement, being expressed as the interval between two standard deviations (± 2SD). The SM
model present-ed a steady error behavior, being independent from the load, de-spite having presented two
volunteers outside the limit of agree-ment, that is, 9.09% of the group. The SF model presented its data
within the 95% of the limit of agreement; however, the error tends to increase as the workload is
increased. When observing the Bland and Altman table(32) applied to the SF (figure 1), one can notice a
tendency in workloads lighter than 12 kg, to overestimate the results, while in workloads heavier than 12
kg, the result is underestimated. Therefore, higher reliability and boldness can be given to the SM model
when compared with the SF model.
DISCUSSION
The 1RM test is usually used for the evaluation of the maximal strength in a single repetition;
nevertheless, massive discussion has been raised concerning its risk of injury(11), as well as its dura-tion
and intensity of muscular discomfort(10) generated from a 1RM test. Massive previous research has
proposed estimations of 1RM workload from submaximal tests, based on the maximum number of
repetitions for a given workload(12-13), on the 1RM percentage(14-15); on the maximal workload for a given
number of repetitions(16-20); on the body mass percentage(10,27); or simply on the anthropomet-ric
characteristics(20-25). The present study follows such panorama, since few studies have been dedicated to
the anthropometric char-acteristics of the Brazilian population. In our study, a 1RM work-load prediction
model was developed in the exercise in develop-ment, exclusively based on the anthropometric variables
and the experience on CRT.
According to the procedures pointed by the literature, all volun-teers performed a previous familiarization
test. Contrary to previ-ous studies(20,33), it did not result in significant differences when comparing test and
retest, so that the repeatability of the mea-sures was guaranteed. Possibly, the experience time of at least
six months in CRT has influenced in this result. In a recent study(14) with young weightlifting athletes, the
experience time was much more correlated to a 1RM than any other anthropometric variable, resulting in
49% of the explained variance. In the present study, the experience resulted in 31% of the 1 RM
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explained variance. Low connections between's the 1RM workload and anthropo-metric variables have
been shown(13,21-22,24-25); therefore, the pre-lingual authority force of 1RM from these variables has a
tendency to be genuinely frail. In any case, in the present study, the arm outline and the trans-versal
segment range (in the SM bunch) brought about 73% of the ex-plained difference, separately. The same
variables (in the SF bunch) acquired weaker results, contributing with 10% of the clarified fluctuation,
individually. On the other hand, the MA introduced low correla-tions (r = 0.35 SM and r = 0.37 SF) with
the 1RM workload. Such discovering conflicts with a late study(34), in which a connection of 0.81
between the MA and the 1RM burden performed in the straight free recumbent activity was found. In an
exceptionally intriguing study(35), such distinction was given to the extensive number of muscles and
joints required amid the execution of the straight prostrate when com-pared with the activity of the
present study, which as indicated by the same authors(35), may prompt distortion of results. The
expectation models of 1RM found here depended on the variables that exhibited the most elevated
incomplete connection coefficients with the 1RM burden. Later, polynomial models from the first to 6th
request were found, that is, with 1-6 free variables. The models results were huge, showing an expansion
in the ex-planation coefficient as free variables are included. Chat ly, the SEE has a tendency to settle,
which gives the feeling that no data is added to the expectation limit of the models. The condition which
introduced the most noteworthy determination coefficient and the least standard blunder of the insights
was utilized as predic-tion model for the estimative of 1RM. In the male people, the expectation model of
1RM brought about 84% of the clarified fluctuation, with standard mistake comparable to 12% (SEE =
6.06 Kg, p < 0.001). Then again, in the SF, the forecast limit of the got model was weaker, result-ing in
56% of the clarified change (SEE = 2.61 kg, p < 0.05) and standard blunder proportional to 20%.
Considering that the specimen group(36), the chose exercise(36), the age(37), the physical condi-tioning
level(14), among different variables may meddle in the intensity of the model, one could expect particular
results amongst SF and SM. Albeit past work has discovered mistake in the 1-10% request with models
taking into account tests of 7-10RM(17-20), considering that in this work just anthropometric estimations
with no physi-cal anxiety were utilized, the outcomes acquired show reasonable consis-tency so that the
models can be considered as an option apparatus for the estimation of the maximal quality. Finally, based
on the results found, it was possible to develop prediction models for 1RM workload in men and women
using exclusively anthropometric variables, resulting in acceptable errors and suitable reliability.
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Figure 1 – Bland and Altman analysis for the prediction of 1RM workload and prediction of the 1RM
equation between the observed load over the load expected in men (lower figures) and women (upper
figures)
Also, in spite of the expectation model of 1RM acquired in the SF gathering being more unobtrusive than
that of the SM, it can be, with some store, taken as adequate. The distinction in the expectation limit in the
male model in examination with the female one was extremely wonderful, which can be connected with
the distinctions in the male and female perfor- mances(38), or with distinct types of strength training(39-40).
In addi-tion to that, men present more muscular mass(38), which tends to result in higher absolute strength
than in women(38). As seen in table 1, the segmental and muscular areas were respectively 96.7% and
116.5% higher in men than in women. While in exercises for lower limbs such difference tends to be
lower or inexistent(38-39), anthropometric differences with magnitude similar to those found here
corroborate the expectation that great differences are found in muscular strength. In a previous study(21 It
is worth mentioning that the present study is restricted to strength measurement of upper limbs, whose
extrapolation for endurance measurements, despite commonly mentioned in the literature, and deserves
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more detailed study, since the prediction of loads equivalent to a higher number of repetitions would
imply in error propagation. Additionally, the group of volunteers is restrict-ed to young individuals with
experience in CRT, so that, a priori, the obtained equations here are limited to application in groups with
such characteristic. It is explicit that the obtained models may be used as potential tools for the prediction
of the 1RM workload in individuals with physical and anthropometric characteristics similar to those described here. Finally, based on the results found, it was possible to develop prediction models for 1RM
workload in men and women using exclusively anthropometric variables, resulting in acceptable errors
and suitable reliability.
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