BEN R. ABADIE
AND MILDRED C. WENTWORTH. Prediction of One Repetition
Maximal Strength from a 5-10 Repetition Submaximal Strength Test in College-Aged
Females. JEPonline,
Vol 3, No 3, 2000. The purpose of this investigation was to develop three
regression equations to predict 1-RM chest press strength (CPS), shoulder
press strength (SPS), and knee extension strength (KES) from a 5-10 RM
CPS, SPS, and KES test in females 19-26 years of age. Thirty healthy
adult females were tested for 1-RM and 5-10 RM strength. The order
of testing was counterbalanced to minimize the effect of improved technique.
Simple regression analysis produced the following equation to predict 1-RM
CPS from submaximal CP testing: [1-RM (lb) = 7.24 + (1.05 SCP)]. The correlation
between predicted and measured 1-RM CP was r = 0.91. The SEE was 2.5 kg
or 7.8% of measured 1-RM CPS. The mean and standard deviations for the
measured 1-RM CPS and the predicted 1-RM CPS was 32.3±5.4 kg and
32.3±6.0 kg respectively. Regression analysis also produced the
following equation to predict 1-RM SPS from submaximal SP testing: [1-RM
(lb) = 1.43 + (1.20 SPS)]. The correlation between predicted and measured
1-RM SPS was r = 0.92. The SEE was 1.6 or 7.6% of the measured 1-RM SPS.
The mean and standard deviations for the measured 1-RM SPS and the predicted
1-RM SPS were 21.4±4.0 kg and 21.4±3.7 kg respectively. Regression
analysis also produced the following equation to predict 1-RM KES from
submaximal KE testing: [1-RM (lb) = 4.67 + (1.14 KES)]. The correlation
between predicted and measured 1-RM KES was r = 0.94. The SEE was 2.3 kg
or 6.3% of measured 1-RM KES. The mean and standard deviations for the
measured 1-RM KES and the predicted 1-RM KES were 38.5±7.6 kg and
38.4±6.8 kg, respectively. The results of this study
indicate that 1-RM CPS, SPS, and KES may be predicted with an acceptable
degree of accuracy in untrained female subjects.
Key
Words: Regression Analysis, Bench Press, Shoulder Press,
Leg Extension Press
INTRODUCTION
Resistance training is an
intricate component of a fitness routine and is one factor of several that
can retard bone mineral loss during aging (1,2).
This is especially true for female subjects, who experience an increased
risk for bone mineral loss after menopause. To prescribe a strength
training program for novice lifters, it is essential to assess an individual’s
muscular strength. A resistance training program is then prescribed based
on a percent of a subject’s maximum muscular strength. The best method
for assessing muscular strength is to determine an individual’s one repetition
maximum (1-RM) lifting capacity. However, this type assessment may be contraindicated
in subjects who have no prior lifting experience (3,4),
since maximal strength testing may produce test induced muscle soreness
and muscular injury from muscle strain in previously untrained individuals.
Based on this realization, several investigators developed submaximal strength
tests to predict 1-RM maximal strength. This assessment allows fitness
instructors to prescribe a resistance training program without subjecting
the individual to a 1-RM strength assessment.
Several investigators have
developed regression equations to predict 1-RM strength from the number
of submaximal lifts performed (3-8). The above studies
were able to predict 1-RM strength in male subjects, based on the number
of repetitions of submaximal weight one could lift. In 1961, Berger
(5) measured 1-RM strength as well as 5-RM and 10-RM
bench press strength. Berger estimated 1-RM bench press from the
weight lifted during the 5-RM and 10-RM strength test. Berger then
developed a chart to predict 1-RM bench press strength from the weight
lifted during the 5-RM and the 10-RM submaximal strength test. The
average percent of 1-RM from the 5-RM and the 10-RM strength tests were
89.8 and 79.9 respectively. The mean percentages were then interpolated
to estimate percentage of 1-RM weight lifted during a 2-RM, 3-RM, 4-RM,
6-RM, 7-RM, 8-RM and 9-RM submaximal strength test. Therefore, one could
perform a submaximal strength test between 2 and 10 lifts and estimate
1-RM strength. The correlation between the measured 1-RM and the
predicted 1-RM strength from the Berger Chart was r = 0.96.
Since the development of
the Berger Chart, several investigators have attempted to refine the prediction
of 1-RM strength. In 1993, Braith et al. (3) attempted
to predict 1-RM knee extension strength from the amount of weight lifted
during a 7-10 RM submaximal strength test. Braith et al. selected 7-10
submaximal strength test because in a training setting, a weight is typically
lifted 7 to 10 repetitions per set. Braith et al. demonstrated the
relationship between measured and predicted 1-RM strength in previously
untrained subjects was linear. The correlation between measured and
predicted knee extension strength was r = 0.94, SEE = 9.3 kg.
Mayhew et al., 1991 (9)
attempted to determine the relationship of structural dimensions of subjects
to bench press strength in college males. Multiple regression analysis
indicated that upper arm cross-sectional area, percent body fat, and chest
circumference could predict 1-RM bench press strength. The correlation
of the prediction of 1-RM bench press strength based on a regression equation
incorporating on the above structural dimensions and the measured 1-RM
bench press strength was r = 0.83, SEE = 11.6 kg.
Little research exists to
predict 1-RM strength from submaximal weight lifted by female subjects.
Rose and Ball (10) evaluated untrained to moderately
trained female subjects 18 to 25 years of age to determine if 1-RM strength
can be predicted from the number of submaximal lifts performed in this
population. Each subject was measured for 1-RM bench press strength and
two submaximal bench press strength assessments. During the submaximal
assessments, subjects were asked to bench press 15.9 kg and 20.4 kg as
many times as they could to determine muscular endurance with these two
weights. Regression analysis using muscular endurance during
the 15.9 kg and the 20.4 kg assessment predicted 1-RM bench press strength
with correlations of r = 0.78 and 0.82 respectively. When body weight was
added to muscular endurance within the regression equation, the correlation
between measured and predicted for the 15.9 kg and the 20.4 kg assessment
increased the correlation r = 0.81 and 0.84 respectively. The above
authors concluded from their study, that the closer the submaximal weight
lifted was to the weight lifted during the 1-RM assessment the more accurate
the regression equation to predict 1-RM strength. The authors also concluded
that the addition of physiological data (i.e., body weight) had minimal
influence on the regression equation to predict 1-RM strength.
Mayhew et al., 1992
(11) required subjects (male and female) to perform
as many correct repetitions of the bench press lifts as possible at a weight
equal to 55 to 95% of 1-RM strength in a one minute period to predict 1-RM
bench press strength. Since the relationship between 1-RM strength
and reps performed during the submaximal strength assessment were not significantly
different in slope and intercept, the investigators combined the data for
males and females. The correlation between measured and predicted
1-RM strength was r = 0.80, SEE = 6.4 kg. These authors also concluded
that the closer the submaximal weight lifted was to the weight lifted during
the 1-RM assessment the more accurate the regression equation to predict
1-RM strength.
In 1998, Cummings and Finn
(12) investigated 57 females 18 to 50 years of age who
had not undergone any muscular strength training to determine if a 4-8
RM submaximal bench press strength test could predict 1-RM bench press
strength. The investigators included the weight lifted during the
4-8 RM submaximal strength test, the number of repetitions performed during
this test, and the biacromial breadth to predict 1-RM bench press strength.
The relationship between predicted and measured 1-RM strength was r = 0.94,
SEE = 1.67 kg.
Regression equations are
specific to variables such as age range, gender, muscle group measured,
and the technique in which the muscle group strength is assessed (i.e.,
free weights or machine weights). The purpose of this investigation
was to develop regression equations to predict 1-RM chest press strength
(CPS), shoulder press strength (SPS), and knee extension strength (KES)
from 5-10 RM CPS, SPS, and KES tests on machine weights in females 19-26
years of age.
METHODS
Subjects
Thirty female subjects 19
to 26 years of age, who have not participated in a strength training program
during the previous year, and were free of physical limitations that would
prohibit them from lifting maximal weight, volunteered to participate in
this study. The procedures of this study were approved by Mississippi
State University's Institutional Review Board.
Procedures
During an orientation session,
the testing procedures and time commitment required for participation in
this study were verbally explained to potential subjects. Following
the orientation, all subjects agreed to participate in this study, and
were asked to complete a medical history form and sign an informed consent
form. Subjects were then assessed for height, weight, age, and percent
body fat based on skinfold calibration (13). A Lange
skinfold caliper was used to take skinfold measurements from seven sites
(14). Body density was determined based on the
Siri equation (15). Resting heart rate,
and resting systolic and diastolic blood pressures were assessed
following a 5-minute seated rest. Following these assessments, subjects
were instructed on the proper lifting technique for performing the chest
press, shoulder press and knee extension press.
During the second and third
testing sessions, subjects were assessed for one repetition maximal (1-RM),
or submaximal 5-10 repetition (5-10 RM) for CPS, SPS, and KES. The
order of testing (1-RM or 5-10 RM strength tests) was randomized to reduce
a learning effect when performing the lifts. All of the strength
assessments were conducted on Sprint weight lifting machines (Hoggan Health
Industries). If subjects were able to perform more lifts than designated
by the testing protocol, subjects were allowed a minimum of 2 min rest
and were reassessed. For the 1-RM test, subjects initially lifted
a weight approximating 50% of the estimated 1-RM. The increments
of weight were dependent upon the effort required for the lift. The
weight added became smaller as the effort to lift the weight increased.
When the subject could only lift the weight once, the last weight successfully
lifted was considered the subject’s 1-RM strength. The 5-10 submaximal
strength test also required subjects to lift a weight initially 25% to
35% of the estimated1-RM. Weight was added in subsequent lifts according
to the procedures stated for the 1-RM assessment. When the subject
could only lift the weight 5-10 times, that weight was considered the subject’s
5-10 RM strength. A minimum of 48 hours separated the 1-RM
and 5-10 RM assessments. Subjects were also asked to refrain from
strenuous physical activity for at least 24 hours before testing.
For all of the 1-RM and 5-10
RM CPS assessments, the movement was performed in a seated, upright
position. The subject grasped the handles, palms down, thumbs over
the bar, hands positioned slightly wider than shoulder width, and seated
in a comfortable position straddling the machine. The lower back
and hips stayed in contact with the back-rest, and subjects were instructed
to keep their feet in contact with the floor. The elbows were held
high, but not over the plane of the shoulder joint. Subjects were
instructed to exhale as they pushed the bar forward until the arms were
near full extended (not locking the elbows). Subjects were instructed
to inhale as they slowly returned the bar to its starting position.
The lift was performed in a controlled manner, taking approximately 2 seconds
for each of the concentric and eccentric phases.
For all of the 1-RM and 5-10
RM SPS assessments, movements were performed in a seated, upright
position, straddling the bench facing the machine. The hands were
positioned on the hand-grips slightly wider than shoulder width.
The palms were facing forward, grasping the hand-grip in an open, relaxed
manner. Subjects were instructed to slide the hips forward until
the shoulders and the hips were aligned vertically under the hand-grips.
During the lift, the subjects pressed the hand-grips upward until the arms
were near full extension, exhaling and without arching the back.
The subjects then returned the weight slowly back to the starting position.
The lift was performed in a controlled manner, as described for the CPS
assessments. The subject’s feet remained in contact with the floor during
the entire lift.
For all 1-RM and 5-10 RM
KES
assessments, the movements were performed in a seated position. The
height of the seat allowed for a 90-degree angle at the knees. Subjects
grasped the handles, palms facing in. Subjects tucked their ankles
behind the roller pad and lifted the roller pad upward, while refraining
from arching the back. Subjects exhaled as they lifted the roller
pad upward until the knees were near full extension. Subjects inhaled as
they slowly returned the roller pad to the starting position. The
lift was performed in a controlled manner, as described for the CPS assessments.
Statistical
Analyses
The following variables
were entered into three stepwise multiple regression analyses to predict
1-RM CPS, SPS and KES: weight lifted during the 5-10 RM submaximal strength
test, repetitions lifted during the 5-10 RM test, age, height, weight,
percent body fat, RHR, RSBP, RDBP, and biacromial breadth. The only
variable selected to predict each of CPS, SPS, KES 1-RM was the weight
lifted during the respective 5-10 RM submaximal strength tests. Therefore,
simple linear regression equations were used to predict 1-RM CP, SP, and
KE strength from the weight lifted during the respective 5-10 RM CPS, SPS,
and KES tests. The accuracy of the regression equation was determined
using the correlation coefficient (r), and the standard error of the estimate
(SEE) between the measured and predicted 1-RM CPS, SPS, and KES.
The SEE was calculated as Sy/1-R2,
where Sy=SD of the measured 1-RM strength and R2
=
the explained variance between the correlated variables. An alpha
level of 0.05 was required for statistical significance. Data are
presented as mean±SD. Weight data are expressed as kg in text,
and due to the equipment used as lb in the regression equations and figures.
RESULTS
The physiological and anthropometric
characteristics of the subject population are presented in Table 1.
Simple regression analysis produced the following equation to predict 1-RM
CP strength from submaximal 5-10 RM CPS testing: [1-RM (lb) = 7.24 + (1.05
SCP)]. The correlation between predicted and measured 1-RM chest press
was r = 0.91. The SEE was 5.5 lb or 7.8% of measured 1-RM CPS. The
mean and standard deviations for the measured and predicted 1-RM CPS were
32.3±5.4 kg and 32.3±6.0 kg respectively. The
relationship between predicted and measured CPS is illustrated in Figure
1.
Table 1. Physiological and
Anthropometric Measurements for Sample Population (N = 30)
Variables Mean±SD
| Variables |
Mean±SD |
| Age (yr) |
22.2±1.2 |
| Height (cm) |
163.3±5.3 |
| Weight (kg) |
62.0±9.7 |
| Body Density (gm/cc) |
1.05±0.03 |
| Body Fat (%) |
21.9±5.4 |
| RHR (b/min) |
67.0±10.2 |
| RSBP (mm Hg) |
119.4±8.9 |
| RDBP (mm Hg) |
73.6±6.3 |
RHR = Resting Heart rate
RSBP = Resting Systolic
Blood Pressure.
RDBP = Resting Diastolic
Blood Pressure
Simple regression analysis
also produced the following equation to predict 1-RM KES from submaximal
5-10 RM knee extension testing: [KES 1-RM (lb) = 4.67 + (1.14 SKE). The
correlation between predicted and measured 1-R KES was r = 0.94. The SEE
was 2.3 kg or 6.3% of the measured 1-RM KE strength. The mean and
standard deviations for the measured and predicted 1-RM KES were 38.5±7.6
kg and 38.4±6.8 kg respectively. The relationship between
predicted and measured KES is illustrated in Figure
2.
Simple regression analysis
produced the following equation to predict 1-RM SPS from submaximal 5-10
RM SPS testing: [1-RM (lb) = 1.43 + (1.20 SPS)]. The correlation between
predicted and measured 1-RM SPS was r = 0.92. The SEE was 1.6 kg or 7.6%
of measured 1-RM SPS. The mean and standard deviations for the measured
and predicted 1-RM SPS were 21.4±4.0 kg and 21.4±3.7 kg respectively.
The relationship between predicted and measured SPS is illustrated in Figure
3.
DISCUSSION
AND CONCLUSION
The results of this study
demonstrated a significant positive correlation between predicted and measured
1-RM CPS, SPS, and KES in 30 untrained female subjects. These results
are consistent with the findings of studies that have attempted to predict
1-RM strength from submaximal strength tests in male (3-8)
and female (10-12) subjects. Based on the limits
of sample size and the use of Sprint weight lifting machines, the regressions
equations generated in this study may be used to predict 1-RM CPS, SPS,
and KES from a 5-10 RM CP, SP, and KE strength test in young adult female
subjects. Unlike several studies reviewed in the introduction, the
current study did not demonstrate that the inclusion of physiological structural
dimensions (9,10,12), or the number of repetitions performed
during the submaximal strength test (5-7,11,12)
improved the accuracy of the regression equations developed in this study.
There were no reported incidents
of muscular injury following the 1-RM or 5-10 RM strength assessments;
3 of the 30 subjects within this study reported mild symptoms of delayed
onset of muscle soreness following the 1-RM strength test. In two
of the three cases, subjects performed the 1-RM strength assessment prior
to performing the 5-10 submaximal strength tests. Both subjects reported
the delayed onset of muscle soreness did not limit their abilities to perform
the submaximal strength test. There were no reported incidents of delayed
onset of muscle soreness following the 5-10 RM submaximal strength tests.
The results of this study support the concerns of previous investigators
(3,4) who believed that a 1-RM test may induce muscle
soreness following the assessment. These findings imply that not
only is the prediction of 1-RM strength from a 5-10 submaximal strength
test practical, the 5-10 submaximal strength test is effective in limiting
the occurrence of delayed onset of muscle soreness that may be associated
with 1-RM strength assessments.
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Address
for correspondence: Ben
R. Abadie, PhD, Mississippi State University, P.O. Box 6186, Department
of HPERS, Mississippi State, MS 39762; Phone: (662) 325-7240; FAX: (662)
325-4525; e-mail: <bra1@ra.msstate.edu>.
Copyright
©1997-2000
American Society of Exercise Physiologists. All rights reserved.
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