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Applied Physiology Research Laboratory, Kent State University, Kent, Ohio 44242
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
ACKNOWLEDGEMENTS
FOOTNOTES
REFERENCES
ABSTRACT 
Roemmich, James N., and Wayne E. Sinning. Weight loss
and wrestling training: effects on nutrition, growth, maturation, body
composition, and strength. J. Appl.
Physiol. 82(6): 1751-1759, 1997.
Adolescent
wrestlers (n = 9, 15.4 yr) and
recreationally active control adolescent males
(n = 7, 15.7 yr) were measured before,
at the end (late season), and 3.5-4 mo after a wrestling season to
assess the influence of dietary restriction on growth, maturation, body
composition, protein nutrition, and muscular strength. Controls
consumed adequate amounts of energy, carbohydrate (CHO), protein, and
fat, and demonstrated normal gains in weight, fat mass (FM) and
fat-free mass (FFM). Wrestlers consumed a high-CHO (61 ± 2% kcal),
low-fat (24 ± 2% kcal) diet during the season but did not consume
adequate energy (24.7 ± 3.5 kcal · kg
1 · day1)
or protein (0.9 g · kg1 · day1).
Deficient dietary intake reduced prealbumin levels (26.0 ± 1.9 vs.
20.2 ± 0.9 mg/dl) and slowed the accrual of lean arm and thigh cross-sectional muscle areas
(AXSECT,
TXSECT, respectively). For
wrestlers, dietary deficiency also decreased weight (60.3 ± 3.5 to
58.0 ± 3.3 kg), relative fat (9.9 ± 0.5 to 8.0 ± 0.7%), and FM (6.0 ± 0.5 to 4.7 ± 0.6 kg). Postseason,
wrestlers and controls consumed similar diets, and wrestlers had
significant increases in prealbumin,
AXSECT, and
TXSECT. Wrestlers also increased their weight (6.1 ± 0.6 kg), FFM (3.0 ± 0.6 kg), and FM (3.2 ± 0.5 kg) postseason. Rates of bone maturation and segmental growth were not different between the groups. The wrestlers had
reductions in elbow and knee strength from preseason to late season but
increases postseason. Lean tissue changes were associated with the
changes in strength and power (r = 0.72-0.91, P < 0.001). After
covariance for FFM or limb-specific cross section, few significant
changes remained. In conclusion, dietary restriction reduced protein
nutrition and muscular performance but produced little effect on linear growth and maturation. Prealbumin levels and the rate of lean tissue
accrual were positively related (r = 0.43, P 
0.05).
adolescence; weight loss; protein nutrition; muscular strength
INTRODUCTION WEIGHT LOSS through dietary restriction has been
speculated to slow the somatic growth (21, 30, 34) of adolescent
wrestlers, although there are no reported effects on growth in height.
Previous studies of pubescent wrestlers have shown that several
skeletal breadths and body girths have decreased incremental growth
during the season and increased incremental growth during the
postseason (26, 29).
The pubertal accrual of fat-free mass (FFM) may also be slowed during
the wrestling season. Longitudinal investigations of body composition
across a wrestling season have shown the FFM to be either unchanged
(14) or nonsignificantly reduced (7, 27). One investigation reported
that the incremental growth in FFM of wrestlers was significantly
slower than other recreationally active youth during the wrestling
season (26), and several studies have reported an accelerated growth in
FFM of wrestlers during the postseason (26, 29). Horswill et al. (12)
speculated that a reduction in the protein nutrition status of
adolescent wrestlers caused by dietary restriction contributed to the
significant reduction in skinfold estimates of FFM. However, no study
has used a criterion method of body composition assessment to
investigate the relationship between changes in the protein nutrition
and FFM of wrestlers or other weight-control athletes.
By impeding the normal adolescent accrual of lean tissue, dietary
restriction may affect strength performance. Previous studies have
shown significant decreases (7, 16, 26), increases (9, 31), or no
change (16, 23) in muscular strength of wrestlers
during a sport season. The purpose of the present study was
1) to relate changes in energy and
nutrient intake that occur during an interscholastic wrestling season
to changes in growth and maturation and
2) to examine the interrelationships
among changes in protein nutrition, body composition, and arm and leg power of adolescent wrestlers. A companion paper (27) discusses the
alterations in growth-related hormones of undernourished wrestlers.
METHODS
135°C.
The blood samples used in this study were obtained as part of the
serial sampling used for hormonal analyses (27).
Nutrition and bone growth activity.
In-season diet records were timed so that the wrestlers had one match
during the 7-day diet-recording period. The early-season diet records
were completed during the first or second week of December, which
coincided with the wrestlers' initial attempt to "make weight"
for competition (Fig. 1). The late-season
diet records were taken before the wrestlers' last match. Subjects were given a verbal explanation of how to properly record the amounts
and types of foods eaten and were shown measuring devices from the
kitchen and food models to help them visualize a single portion. Diet
records were analyzed with the West Nutrition Program (West Publishing,
St. Paul, MN). Macronutrients were examined as the percentage of total
energy provided and as the amount of nutrient consumed per kilogram
body weight per day. Plasma prealbumin was measured by radial
immunodiffusion plates (Behring Diagnostics, La Jolla, CA). BUN was
assessed by using Sigma kit no. 640-A (Sigma Chemical, St. Louis, MO).
Alkaline phosphatase was measured with a photometric assay (no. 245, Sigma Chemical).
1 · day1),
protein
(g · kg1 · day1),
fat
(g · kg1 · day1),
and carbohydrate (CHO;
g · kg1 · day1)
for the wrestler (
, n = 9) and
control (
, n = 7) groups at times
early and late in the season and postseason. Like letters indicate
significant difference. Values are means ± SE.
Anthropometry and physical maturation. All measures were made by one experienced anthropometrist (J. N. Roemmich). The recommendations of Lohman et al. (19) were followed relative to landmarks and methods. Except for skinfold thicknesses, each variable was measured three times; the median score was used to avoid the effects that an outlying measure might have on the mean score. Skinfold thicknesses were measured until three at each site were within 5% of each other; the mean was then computed. The skeletal lengths included stature, sitting height, and the lower extremity, hand, forearm-hand, elbow-wrist, shoulder-elbow, thigh, and calf lengths. Breadths taken were the biacromial, transverse chest, anterior-posterior chest, bi-iliac, elbow, wrist, knee, and ankle. Circumference measures included the wrist, forearm, flexed midarm, shoulder, chest, natural waist, abdomen, hip, thigh, and calf. Skinfold-thickness sites included the subscapular, triceps, biceps, chest, suprailiac, abdominal, thigh, and midcalf. The flexed lean (muscle plus bone) cross-sectional area of the midarm (AXSECT) was measured as previously described (26). The relaxed lean midthigh cross-sectional area (TXSECT) was computed by using the midthigh girth and midthigh skinfold (26). All anthropometric measurements were taken at the same time of day in each testing period. The reliability of the anthropometrist was assessed by using within-day replicate measures. The technical error of measurement (
e) and a
coefficient of variation (CV) were calculated (20) for several
important anthropometric measures and are reported in Table
1. The e and CV are equal to or less than those of other experienced anthropometrists (20).
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0.05 was
chosen.
RESULTS
chronological age)
remained constant for both groups. The hematocrit did not change for
the wrestlers (41.1, 42.8, 42.6%) or controls (43.5, 43.4, 43.5%) at
pre-, late, or postseason.
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, n = 9) and controls
(, n = 7). Like letters indicate
significant difference. Values are means ± SE.
The energy intake and body weight were reported daily (Fig. 3) to illustrate how the wrestlers altered their energy intake to make weight. The wrestlers consumed more energy Sunday and Monday than the day before competition (Friday). To cut weight for competition, the wrestlers consumed less energy than the controls on Wednesday, Thursday, and Friday. The controls' body weight (Fig. 3) did not change, whereas the wrestlers' body weight steadily decreased Sunday through Saturday. All post hoc comparisons between days were significant except the comparison between Tuesday and Sunday. The mean weight lost between Monday and Saturday to make the competitive weight was 2.8 kg or a reduction of 4.8%. The mean weight loss from the preseason weight to make the competitive weight was 4.5 kg or a reduction of 7.4%.
,
n = 9) and controls (,
n = 7) during 1 wk, with weight certification for wrestlers on Saturday. Like letters indicate significant difference. Values are means ± SE.
Body composition. Significant group-time interactions were found for changes in weight, %BF, fat mass (FM), and FFM (Table 2). The controls increased their weight and FFM from pre- to postseason but did not change their %BF or FM. The wrestlers lost weight, FM, and %BF from preseason to late season and then gained a significant amount postseason. The in-season decrease in FFM of 1.1 kg was not significant, but the postseason increase (3.0 kg) was significant. The pre- to postseason increase in FFM (1.9 vs. 2.1 kg) was similar for both groups. As expected, the growth increments for weight (
3.72 kg/6 mo, <3rd percentile
for age) and FFM (1.92 kg/6 mo) of the wrestlers
were significantly lower during the sport season than the postseason
(9.29 kg/6 mo, >97th percentile for age; and 4.49 kg/6 mo,
respectively). The controls had sport seasonal and postseasonal weight
increments of 3.19 kg/6 mo (63rd percentile for age) and 1.60 kg/6 mo
(37th percentile for age) and FFM increments of 2.5 and 0.9 kg/6 mo.
The weight increment for the wrestlers from pre- to postseason (2.9 kg/6 mo, 62nd percentile for age) was similar to the controls (2.4 kg/6
mo, 54th percentile for age) (4).
Anthropometrics.
The pre- to late-season and late- to postseason corrected height
increments of the wrestlers (1.46 ± 0.24 cm/6 mo, 46th percentile for age vs. 1.78 ± 0.41 cm/6 mo, 56th percentile for age)
and controls (2.32 ± 0.47 cm/6 mo, 55th percentile vs.
1.81 ± 0.54 cm/6 mo, 57th percentile) did not produce
significant main or interaction effects. Both the wrestlers' (1.76 ± 0.32 cm/6 mo, 55th percentile) and the controls' (2.16 ± 0.48 cm/6 mo, 66th percentile) pre- to postseason height increments
were within the normal range (4). For the segmental lengths and
skeletal breadths, there were many significant time effects, but only
shoulder-elbow length and elbow-wrist length had significant
interactions (Table 3). For both
shoulder-elbow and elbow-wrist length, controls increased over
preseason values at both late season and postseason. The wrestlers'
shoulder-elbow length increased from pre- to postseason.
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,
n = 9) and controls (,
n = 7). Like letters indicate
significant difference. Values are means ± SE.
Lean limb cross-sectional areas are commonly used as markers of protein nutrition and are thought to reflect muscle protein reserves (10). The AXSECT and TXSECT (Table 1) of the controls increased significantly from pre- to postseason. Despite training from preseason to late season, the wrestlers AXSECT did not change, whereas the TXSECT decreased. Both increased significantly postseason. The pre- to postseason increases in AXSECT (8.1 vs. 8.8 cm2) and TXSECT (4.8 vs. 5.4 cm2) were similar for both groups. Strength and power. Elbow peak power and torque changes are shown in Table 4. There were no significant changes for the controls, but from preseason to late season the wrestlers' peak torque decreased for elbow flexion (EF) at 60°/s and elbow extension (EE) and EF at 180°/s. The wrestlers' peak arm power decreased from preseason to late season for EE and EF at 180°/s. For the wrestlers, all measures increased significantly postseason. The AXSECT and FFM were directly related to arm strength and power (r = 0.80 to 0.90, P < 0.001). After covariance for FFM and AXSECT, only the wrestlers' EF torque at 60°/s and EF torque and power at 180°/s remained reduced from preseason to late season and increased postseason.
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1 · wk1).
The physical activity of the controls was not significantly changed (25 vs. 36 kcal · kg1 · wk1).
Physical activity values for the groups were significantly different
during the sport season.
In general, wrestling practice sessions consisted of live wrestling
(45-90 min), wrestling drills (20-45 min), calisthenics (10-20 min), instruction (10-20 min), and running (10-25
min). Wrestlers participated in basketball
(n = 2, 45-60 min) and running (n = 1, 20 min) on Sunday. No wrestler
listed weight training as an activity during the sport season. Five of
the controls were Boy Scouts and participated in many outdoor
activities. All of the control subjects were recreationally active in
sports such as tennis, off-road motorcycling, bicycling, basketball,
and baseball.
DISCUSSION
This investigation is novel because it is the only study of adolescent wrestlers to investigate the interactive effects of energy drain on growth and maturation, including bone age. Also, the actual undernutrition of adolescent wrestlers has not been well documented. One investigation (12) reported the energy intake of adolescent wrestlers, but the present study is the only one to estimate both the energy intake and expenditure. In addition, although other studies (7, 12) have investigated the relationship between changes in body composition and strength in adolescent wrestlers, they did not include a nonwrestling control group, did not report alterations in growth or maturation, and in one study (12) the body composition was estimated from skinfolds. In the present study, the subject groups were initially matched for physical characteristics and maturational status. Therefore, a valid comparison can be made regarding the influence of wrestling training and dietary restriction on growth, maturation, and body composition.
Despite participation in 65% more physical activity than the controls
during the sport season, the wrestlers' early- and late-season energy
intake (Figs. 1 and 2) was roughly 50% of the recommended 48 kcal · kg1 · day1
(8). The wrestlers' postseason energy intake was similar to the
controls and close to the recommendation. Horswill et al. (12) also
reported deficient in-season and adequate out-of-season energy intakes
of adolescent wrestlers (27 vs. 43 kcal · kg1 · day1,
respectively). Thus, despite position statements on weight loss (2, 3),
wrestlers continue to lose weight by severe dietary restriction. The
mean in-season protein intake was also similar to that reported by
Horswill et al. (12) of 0.9 g · kg1 · day1.
The recommended minimum protein intake for this age is 0.97 g · kg1 · day1
(8), but the protein intake may be even more deficient than these data
suggest. The protein requirement is higher during physical training
(17), periods of reduced energy intake (6), and growth (8), all
conditions that were present in the wrestlers.
A unique aspect of this study is the documentation of the change in energy intake and weight during the days leading up to a competition (Fig. 3). In conflict with the common belief that rapid fluctuations occur in weight and energy intake before a match, the wrestlers reduced their weight and energy intake in a linear manner. On no day during the week did the wrestlers consume enough energy to meet the combined requirements of growth, resting metabolic activity, and training, suggesting that they were in a constant state of undernutrition throughout the week. If this week is representative, the entire season would be characterized by graded undernutrition as supported by our prealbumin findings (Fig. 3).
The undernutrition does not appear to slow pubertal maturation (Table
2), as indicated by the wrestlers' slightly advanced bone ages, stable
relative ages (bone age chronological age), and pubertal stages
within the normal range (24, 32). Continuing skeletal maturation and a
slowing in linear growth could result in a wrestler's not attaining
his genetic potential for height. However, as in previous reports, the
wrestlers' incremental growth in stature was similar to the controls
both during the season and postseason (13, 26), and the alkaline
phosphatase activity suggested no change in bone growth metabolism. The
skeletal breadths also demonstrated little difference in the rate of
bone growth between the wrestlers and controls. Although there was a
lack of change in elbow-wrist length of the wrestlers (Table 2), this may have been due to systematic measurement error (Table 1). Also, a
significant loss of skinfold thickness from preseason to late season
(77.5 ± 5.4 to 61.5 ± 4.2 mm) may have reduced the
fat-skin layer over the upper limb landmarks, creating a situation where growth of the bones appeared to slow. The fat-skin layer increased during the postseason (sum of skinfolds = 97.4 ± 4.2 mm).
In agreement with previous findings (14, 26), the wrestlers' body
girths decreased from preseason to late season and increased from late
season to postseason (Table 2). The wrestlers' large postseason
increments in girth demonstrate an accelerated growth in
soft tissue after the wrestling season.
The mean %BF (10.5%) of the control group was low for recreationally active youth but allowed matching the groups for adiposity. Even though the in-season reduction in FFM was not statistically significant, it may be biologically significant. The FFM increased for the controls and was related to the loss of arm and leg strength in the present and past studies (26). The wrestlers' weight and FFM increased at an accelerated rate during the postseason, as reported previously (26, 29). Alterations in the hydration of the wrestlers had the potential to influence the body composition results. However, the body composition measurements took place when the subjects should have been euhydrated (see METHODS). Furthermore, the hematocrit was not changed for either group.
Horswill et al. (12) speculated that the lack of lean tissue accrual by
adolescent wrestlers was due to a reduction in protein nutrition and
muscle protein synthesis. Prealbumin (Fig. 4) is a sensitive marker of
marginal protein or energy intake in apparently healthy children and
serves as a marker of malnutrition before clinical complications are
evident (15). The modest relationship (r = 0.43, P 0.05) between the late-season
prealbumin concentration and the preseason to late-season change in FFM
may be limited by prealbumin's being more of an indicator of visceral
protein status (5) rather than the entire FFM. Reductions in serum prealbumin concentration are caused by a reduction in its synthesis in
the liver (15). Reduced protein synthesis in other tissues, especially
muscle tissue, would slow the physical development of the adolescent
wrestler (12). Although we have no direct measures of protein
synthesis, the wrestlers' mean FFM was 2.0% lower (a nonsignificant
change), as in a previous study (26), and the normal adolescent
increase in the lean limb cross-section (10) was significantly slowed
or reversed from preseason to late season (Table 2). An
increase in protein catabolism could also slow lean tissue accrual, but
the wrestlers' BUN concentrations were not significantly changed.
After covariance of the muscle performance data for FFM or cross section, only 2 of 26 measures remained significant, suggesting that changes in power are primarily related to changes in lean tissue, as previously reported (7, 16, 26). A change in the wrestlers' strength training regimen or an overtraining effect may have contributed to the change in muscle performance. None of the wrestlers included weight training as a part of his in-season workout, but during the postseason six of the nine wrestlers did weight training 3-4 days a week. The influence of weight training on the muscle mass and strength of wrestlers during the sport season is uncertain.
The reduction in arm and leg strength and power during the wrestling season should be of concern to the wrestler and the coach, as the importance of power for wrestling success has been previously established (25). The reduction in muscular strength and power relative to the loss of lean tissue conflicts with the theory that weight loss allows a participant to gain a competitive edge. However, successful wrestlers have been reported to reduce a greater percentage of their body weight than less successful wrestlers, and many factors other than strength are related to wrestling success (25). Perhaps the most successful wrestlers are those who are able to reduce their weight and still maintain their strength and power by limiting the loss of FFM. Through differences in weight-loss regimens and nutrition, successful wrestlers may also limit losses of muscle glycogen. Investigations of acute weight loss with low-energy, high-carbohydrate diets have demonstrated a maintenance of performance in collegiate wrestlers (11). However, the strength and power reductions in the present study were influenced by a sport season of weight maintenance in less physically mature high school wrestlers.
In conclusion, dietary restriction and wrestling training had little effect on bone growth or maturation. Dietary restriction did produce significant reductions in protein nutritional status, body protein and fat stores, and muscular strength and power. All were quickly reversed during the postseason when the wrestlers decreased their physical activity and increased their energy intake. During the sport season, changes in lean tissue were directly associated with changes in protein nutritional status. The reductions in strength and power during the sport season were primarily associated with the loss of lean tissue. Subsequent studies should measure, by using stable isotopes, the rate of protein synthesis of wrestlers.
ACKNOWLEDGEMENTS
We thank the subjects, parents, and wrestling coaches for their participation and cooperation. We thank Dr. Craig Horswill for helpful insights and contributions to the data interpretation and discussion, and we thank Dr. Alan D. Rogol for suggestions during preparation of the manuscript.
FOOTNOTES
Address for reprint requests: J. N. Roemmich, Univ. of Virginia Health Sciences Center, Dept. of Pediatrics, Div. of Endocrinology, Box 386, Charlottesville, VA 22908 (E-mail: jr5n{at}virginia.edu).
Received 26 July 1996; accepted in final form 6 February 1997.
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