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109
Journal of Strength and Conditioning Research, 2003, 17(1), 109–114
q 2003 National Strength & Conditioning Association
Strength Changes During an In-Season
Resistance-Training Program for Football
JAY R. HOFFMAN AND JIE KANG
Department of Health and Physical Education, The College of New Jersey, Ewing, New Jersey 08628.
ABSTRACT
The purpose of this study was to examine the effects of both
intensity and volume of training during a 2 d·wk21 in-season
resistance-training program (RTP) for American football
players. Fifty-three National Collegiate Athletic Association
Division III football players were tested in the 1 repetition
maximum (1RM) bench press and 1RM squat on the first day
of summer training camp (PRE) and during the final week
of the regular season (POST). Subjects were required to per-
form 3 sets of 6–8 repetitions per exercise. Significant
strength improvements in squat were observed from PRE
(155.0 6 31.8 kg) to POST (163.3 6 30.0 kg), whereas no PRE
to POST changes in bench press were seen (124.7 6 21.0 kg
vs.123.9 6 18.6 kg, respectively). Training volume and train-
ing compliance were not related to strength improvement.
Further analysis showed that athletes training at $80% of
their PRE 1RM had significantly greater strength improve-
ments than athletes training at ,80% of their PRE 1RM, for
both bench press and squat. Strength improvements can be
seen in American football players, during an in-season RTP,
as long as exercise intensity is $80% of the 1RM.
Key Words: athletic performance, bench press, period-
ized training
Reference Data: Hoffman, J.R., and J. Kang. Strength
changes during an in-season resistance-training pro-
gram for football. J. Strength Cond. Res. 17(1):109–114.
2003.
Introduction
The in-season resistance-training program (RTP) forteam sports is a maintenance phase of the athlete’s
annual periodized training program, in which the pri-
mary focus is on maintaining the strength gains made
during the earlier phases of training. Studies indicated
that strength increases can be made during this phase
of training but primarily in a previously untrained
athletic population (9, 12). In athletes with resistance-
training experience, the in-season RTP may only main-
tain the strength gains that were attained during the
off-season training program (1, 9). However, if an in-
season RTP is not part of the athlete’s in-season prac-
tice routine decrements in strength (detraining) were
seen in both strength-trained (4) and athletes with
minimal (5 weeks) resistance-training experience (9).
In-season RTP’s for team sports are typically per-
formed twice a week (6, 9, 10, 12). The program design
for this phase of training primarily focuses on main-
taining the core exercises from the off-season training
program and eliminating many of the assistance ex-
ercises (11). In-season training programs generally
used 3 sets per exercise and between 6–8 repetitions
in the strength/power exercises (i.e., bench press and
squat), and 3–5 repetitions in the Olympic exercises
(i.e., power clean and push press) (10, 12).
Despite the important contribution of strength and
power to the success of the American football player
(2, 3, 7, 15), there are no published studies in the last
30 years examining the effects of an in-season RTP on
strength performance in American football players.
Recent studies examining in-season RTP’s have used
basketball players as the subject population (10, 12).
Although strength gains made during the off-season
were maintained in experienced, resistance-trained
athletes, and improved in novice athletes, differences
in the physical and physiological demands between
basketball and football may result in a different re-
sponse to an in-season RTP. Both football and basket-
ball players perform repeated bouts of high-intensity
exercise; however, the football player is also subjected
to violent physical contact with his opponent or play-
ing surface. This may result in muscle tissue damage,
as recently evidenced by significant elevations of mus-
cle enzymes (i.e., myoglobin) after a football game
(13). This added physical stress associated with foot-
ball may prevent the athlete from maintaining the re-
quired training intensity and training volume during
the in-season RTP. Thus, the ability to maintain
strength in these athletes may be compromised. Thus,
this study examined the effects of a competitive foot-
ball season on in-season strength changes, specifically
testing the influence of acute program variables (i.e.,
training intensity, training volume, and training com-
pliance) on strength improvements. In addition, com-
parisons between experienced and inexperienced col-
110 Hoffman and Kang
Table 1. Inseason resistance training program.*
Exercise
Sets 3
repetitions
Power clean
Squat
Push press
Bench press
1, 3 3 3–5
1, 3 3 6–8
1, 3 3 4–6
1, 3 3 6–8
* The first number in front of the comma refers to a warm-
up set. The number after the comma refers to how many
‘‘work sets’’ were to be performed.
lege football players about in-season strength changes
were also examined.
Methods
Subjects
Fifty-three members of a National Collegiate Athletic
Association (NCAA) Division III football team (mean
6 SD; 19.7 6 1.4 years; 178.1 6 6.4 cm; 91.4 6 16.3
kg) volunteered to participate in a 2 d·wk21 in-season
RTP. The subjects gave their informed consent as part
of their sport requirements consistent with the insti-
tution’s policies of our institutional review board for
use of human subjects in research. Subjects were test-
ed for maximal strength at the onset of pre-season
practice (PRE) (start of 2-a-day training sessions) and
during the final week of the regular season (POST) (12
weeks later).
In-season RTP
The in-season RTP can be seen in Table 1. The exercises
selected for the in-season RTP were the core exercises
from the subjects’ off-season conditioning program. In
addition, the in-season RTP was not periodized and
was treated as 1 mesocycle of the athlete’s yearly train-
ing program. This approach is similar to that seen
elsewhere for in-season training programs (6, 9, 10,
12). For instance, subjects were provided a range of
repetitions to perform for each exercise. Subjects were
required to perform between 6–8 repetitions for the
bench press exercise. That is, they needed to select a
resistance that they could perform for at least 6 but not
more than 8 repetitions. If they believed that they
could perform an additional repetition, then this resis-
tance was considered too light, and they were instruct-
ed to increase the weight used. This repetition range
equated to approximately 80% of the subject’s 1 repe-
tition maximum (1RM) and was required for both the
bench press and squat exercises (6). Subjects were also
instructed to increase the resistance if they performed
the maximum number of repetitions required for 2
consecutive exercise sessions. Because of injuries, fa-
tigue, and the expected wear and tear that the football
player experiences during a season, the actual resis-
tance used per exercise session was left to the subject’s
discretion.
Subjects recorded all workouts in a logbook. The
logbook was collected by one of the investigators after
each workout, and the total volume (resistance used 3
total number of sets 3 total number of repetitions) for
all exercises and the intensity (% of PRE 1RM) for only
the bench press and squat exercises were recorded. At
the end of the season the average weekly training vol-
ume and training intensity were used for subsequent
analyses.
Strength and Anthropometric Testing
During the pre-season testing period, the strength
tests were part of a complete testing battery that in-
cluded speed (40-yd sprint), agility (T-drill), vertical
jump height, and anthropometric measures. During
posttesting, only the strengthtests were performed.
During the pre-season testing period, the 1RM bench
press and squat tests were performed at least 30 min-
utes after the speed and agility testing.
One repetition maximum bench press and squat ex-
ercise tests were performed to measure upper- and
lower-body strength (14). The 1RM tests were con-
ducted as described by Stone and O’Bryant (17). Sub-
jects warmed up with a light resistance and then
achieved a 1RM effort within 3–5 attempts. No bounc-
ing was permitted because this would have artificially
boosted strength results. Bench press testing was per-
formed in the standard supine position: the subject
lowered an weightlifting bar to midchest and then
pressed the weight until his arms were fully extended.
The squat exercise required the player to rest an
weightlifting bar across the trapezius at a self-chosen
location. The squat was performed to the parallel po-
sition, which was achieved when the greater trochanter
of the femur was lowered to the same level as the knee.
The subject then lifted the weight until his knees were
extended. Studies demonstrated good test-retest reli-
abilities (r . 0.90) for these strength measures (8, 9).
Anthropometric assessments included height, body
weight, and body fat content. Body weight was mea-
sured to the nearest 0.1 kg. Body fat content was es-
timated from skinfold caliper measures using the
method of Durnin and Wormersely (5).
Statistical Analyses
In-season RTP for strength and anthropometric mea-
sures was assessed by paired Student’s t-tests. The ef-
fect of intensity of training on pre- to post- (D)
strength measures was evaluated by an unpaired Stu-
dent’s t-test. Subjects who on average trained at the
required exercise intensity ($80% of their PRE 1RM)
were compared with those subjects who on average
trained below the required exercise intensity (,80%)
for the entire season. In addition, D strength and an-
thropometric comparisons between inexperienced sub-
In-Season Resistance-Training Program for Football 111
Table 2. Strength and anthropometric performance re-
sults.
Pre Post
1RM† bench press (kg)
1RM squat (kg)
Body weight (kg)
Body fat %
124.7 6 21.0
155.0 6 31.8
91.4 6 16.3
16.2 6 4.6
123.9 6 18.6
163.3 6 30.0*
92.0 6 16.4
16.7 6 4.7
† RM 5 1 repetition maximum; * significant pre- to post-
difference, p , 0.05.
Figure 1. (a) Average weekly training intensity for the
bench press exercise. (b) Average weekly training intensity
for the squat exercise.
Figure 2. Average weekly training volume (sets 3 repeti-
tions 3 weight).
jects (in their first year of college) and experienced
subjects (in their final year of football eligibility) were
also analyzed with an unpaired Student’s t-test. Pear-
son product-moment correlation was used to examine
selected bivariate correlations.
To examine factors relating to in-season strength
improvements a linear regression analysis, using a
stepwise regression model, was used with D strength
scores as the dependent variables and training inten-
sity, training volume, training compliance, pre-season
strength level, and year in school as independent var-
iables. On the basis of studies that examined in-season
strength programs (9, 11), a sample size of 55 subjects
would provide at least 90% statistical power at an a
level of 0.05 (2-tailed). All data are reported as mean
6 SD.
Results
The effects of the in-season RTP are presented in Table
2. A significant (p , 0.05) increase in 1RM squat
strength was seen during the competitive football sea-
son. No other significant pre- to postseason changes
were seen.
Weekly training intensities for the bench press and
squat exercises are presented in Figure 1a,b, respec-
tively. In general, the average training intensity (rela-
tive to pre-season 1RM) for the bench press exercise
increased during the season. For the squat exercise, the
mean training intensity (relative to pre-season 1RM)
was below 80% during the first 2–3 weeks of the sea-
son and then increased to 80% and remained there for
the duration of the season. Changes in training volume
can be seen in Figure 2. Training volume increased
during the initial weeks of the season and then ap-
peared to plateau for the remainder of the season.
Comparisons between college football players in
their first year (freshman) (n 5 14) and those in their
final year of football eligibility (seniors) (n 5 13) can
be seen in Figure 3. No significant difference in D1RM
bench press was observed between the groups. How-
ever, improvements in the D1RM squat were signifi-
cantly greater in the freshman subjects than in subjects
in their senior year. In addition, no difference in body
mass changes was seen between freshman and senior
subjects (1.7 6 2.1 kg vs. 0.8 6 2.2 kg, respectively)
during the course of the football season.
Pearson product-moment correlations between
strength performance and intensity and volume and
training compliance can be seen in Table 3. A mod-
erate, but significant correlation (p , 0.05) was seen
112 Hoffman and Kang
Figure 3. D Strength comparisons between freshmen and
senior football players. * 5 Significant difference between
the groups (p , 0.05).
Table 3. Pearson correlation coefficients between
strength performance and intensity, volume, and training
compliance.
D1RM
bench
press
D1RM
squat
Training intensity (% 1RM)
Training volume (weight 3 sets 3 repe-
titions)
Compliance (% of workouts completed)
0.68*
0.17
20.01
0.47*
20.12
20.02
* Indicates significant correlation to strength changes (p ,
0.05).
Table 4. Regression analysis.
Variable b SEb r r2
Signifi-
cance
(a) Bench press strength improvement
Constant
Intensity
2167.1
205.2
25.3
31.2 0.68 0.46 0.000
(b) Squat strength improvement
Constant
Intensity
2102.1
151.7
32.2
40.4 0.47 0.22 0.000
Figure 4. The effect of training intensity on D1RM bench
press and D1RM squat exercises. * 5 Significant difference
between the groups (p , 0.05).
between increases in D strength in the bench press ex-
ercise and intensity of training. In addition, a low-to-
moderate correlation (p , 0.05) was also seen between
increases in D strength in the squat exercise and the
intensity of training.
The linear regression analysis for changes in bench
press and squat strength measures are listed in Table
4. The only predictor to make each equation was the
intensity of training for each respective exercise. For
the bench press exercise, intensity of training was able
to explain 46% of the variance in strength changes,
whereas for the squat exercise the intensity of training
was able to explain 22% of the variance in 1RM squat
strength improvement.
In the squat exercise, 44% of the subjects were able
to maintain an average training intensity for this ex-
ercise $80% of PRE 1RM, whereas most subjects
trained at an intensity ,80% of PRE 1RM (85.1 6 3.6%
and 76.4 6 1.9%, respectively) for the duration of the
season. From Figure 4 it can be seen that D1RM squat
strength was significantly greater in subjects whose
average training intensity for the squat exercise ex-
ceeded 80% during the season compared with subjects
whose training intensity for the squat exercise was
,80%.
The effects of intensity of training and D1RM bench
press strength can also be seen in Figure 4. Average
training intensity for this exercise during the season
exceeded 80% (86.8 6 5.3%) in 51% of the subjects,
whereas the remainder of subjects trained with a re-
sistance that was below 80% (72.6 6 5.13%). The re-
sults of strength changes showed that subjects who
trained at an exercise intensity $80% realized a 7.2 6
27.0 kg improvement in upper-body strength, whereas
subjects training at ,80% saw a 9.4 6 10.5 kg reduc-
tion. However, these differences between the groups
were not significant.
DiscussionThe results of this study suggest that strength increas-
es can occur during an in-season RTP in NCAA Di-
vision III college football players. When the subjects
were examined as a group (including both experienced
and inexperienced resistance-trained athletes),
strength improvements were seen only in the lower
body (e.g., 1RM squat), whereas strength was main-
tained in the upper body (1RM bench press). This dif-
fers from studies that demonstrated significant im-
In-Season Resistance-Training Program for Football 113
provements in bench press strength, with no signifi-
cant change in squat strength, during an in-season
RTP in basketball players (10, 12). In these previous
studies, strength increases were reported only in sub-
jects who had minimal resistance-training experience
(approximately 1–2 months). In subjects with a year
or more of resistance-training experience, no signifi-
cant improvements in either bench press or squat
strength were seen. In this present study, all the sub-
jects had resistance-training experience. This is the
first study known to demonstrate that strength im-
provements can be achieved during a competitive sea-
son even in experienced resistance-trained college
football players.
In this study the ability to improve lower-body
strength, while maintaining only upper-body strength
in collegiate basketball players contrasts with the re-
sults of Hoffman et al. (12). According to the earlier
study, specific fatigue patterns in the lower body (re-
sulting from a high number of games and scrimmages
during practices) might prevent even relatively novice
resistance-trained basketball players from significantly
improving lower-body strength during the season (10,
12). However, considering the results found in this
study it is likely that the relatively consistent practice
(2 full pad practices) and game (1 per week) schedule
of football players permit training to occur on days
that practices are at a reduced intensity and volume,
allowing for a more productive workout. In this study,
typical days of in-season training were on Mondays
and Thursdays. Monday workouts generally occurred
48 hours after the game and either occurred before or
after football practice (no contact practice, players’
dress in shorts, T-shirt or sweats, and helmet). The
Thursday workout occurred after practices when the
subjects were required to wear only shoulder pads and
helmets with no full contract drills occurring. Subjects
were encouraged to lift during the day before practice.
However, if subjects were unable to lift because of con-
flicts with their class schedule they were then required
to lift after practice. In addition, although the subjects
of this study had been resistance training for several
years, generally beginning during their high school
football careers, for most subjects this was the first
time they were involved in a training program that
was supervised by a strength and conditioning coach.
Mazzetti et al. (16) demonstrated that direct supervi-
sion of a heavy RTP in moderately trained individuals
can significantly improve strength performance dur-
ing a period (12 weeks) that was similar to the dura-
tion of the in-season RTP of this study.
The effect of a supervised training program could
also contribute to the different patterns of strength
changes seen between the bench press and squat ex-
ercises. Empirically, the bench press is a relatively eas-
ier exercise to master than the squat. Because of the
difficulty in performing the squat exercise, many ath-
letes who are not required to do this exercise as part
of their training program may opt for a less difficult
exercise (i.e., leg press) to train their lower body. The
resistance training experience of the subjects in this
study probably resulted in a relative high level of per-
formance in the bench press exercise. Although most
of the subjects had performed the squat exercise before
this study, their technical ability for this exercise (i.e.,
bar placement, knee and foot alignment, and lowering
to parallel) varied widely. Because proper technique
was stressed during the training and testing program,
it is possible that the subjects had a larger window of
opportunity for strength gains based on improved
technique in the squat exercise compared with the
bench press exercise. Thus, the strength improvements
seen in the squat exercise could be partially attributed
to a learning effect.
Training intensity may be the only acute program
variable that was able to predict strength improvement
in both the bench press and squat exercises. Neither
training volume, pre-season strength level, year in
school (i.e., freshman, sophomore, etc.) nor training
compliance were able to significantly add to the vari-
ance in strength improvement for either exercise. The
importance of training intensity was also demonstrat-
ed when comparing D strength changes in both the
squat and bench press exercises in subjects training at
above or below 80% of their PRE 1RM. Although sig-
nificant improvements in squat strength were seen in
subjects training either above or below 80% of their
PRE 1RM, those subjects training $80% had a 2.5-fold
greater (p , 0.05) strength gain than did subjects train-
ing at the lower exercise intensity. In contrast, subjects
who trained at ,80% 1RM in the bench press exercise
tended to lose strength (p . 0.05) during the season,
whereas subjects able to maintain or exceed the re-
quired exercise intensity (80% 1RM) for the duration
of the in-season tended to improve upper-body
strength.
Training compliance refers to the percentage of re-
sistance-training sessions that the subjects trained out
of the total number of possible training sessions. In-
jury was the primary factor affecting training compli-
ance. However, there were instances when conflicts be-
tween class, practice, and study also contributed to
missed sessions. For the bench press exercise, subjects
trained in 91.0 6 11.6% of all possible training ses-
sions, and for the squat exercise subjects trained dur-
ing 85.9 6 17.5% of all possible training sessions.
Training compliance did not have any effect on
strength gains. However, in instances of a season-end-
ing injury, in which the subject was unable to complete
the postseason strength testing, those subjects were
excluded as subjects in this study.
Training volume, reported as load 3 repetitions 3
sets, tended to increase during the season. This is ex-
pected considering that the relative intensity of the
114 Hoffman and Kang
training program was maintained, and that the normal
progression of training (e.g., increasing the training
load as the subjects were able to complete the required
number of repetitions per set) would likely result in
an increase in training volume. Considering that train-
ing volume had little to no correlation to strength im-
provements, it may not be a significant factor contrib-
uting to in-season strength gains.
Resistance-training experience does affect the abil-
ity of athletes to improve strength during the season
(12). In this present study we were able to examine
this relationship again. Specifically, we wanted to com-
pare those subjects who would likely have the least
resistance-training experience (freshman subjects) and
the subjects who likely had the most resistance-train-
ing experience (senior subjects in their final year of
football eligibility). Comparisons between the fresh-
man and senior subjects revealed no significant differ-
ences in D body mass or D1RM bench press. However,
subjects in their first year of college football eligibility
had a significantly greater increase in squat strength
than subjects in their final year of eligibility (15.1 6
6.4 kg vs. 5.5 6 8.2 kg, respectively). These results are
expected considering that individuals with greater
training experience would be closer totheir genetic
potential and their window of adaptation for strength
improvement would be reduced (6).
Practical Applications
This study demonstrates that significant strength im-
provements can be achieved during the season in a
Division III college football team. Intensity of training
is the most important variable associated with these
strength changes. Although strength improvements
can be seen in both experienced and less experienced
athletes, the less experienced resistance-trained foot-
ball player does have a greater potential for strength
improvement during a season of competition.
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