Long-term effect of nutritional counselling on desired gain in body mass and lean body mass in elite athletes

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1 547 Long-term effect of nutritional counselling on desired gain in body mass and lean body mass in elite athletes Ina Garthe, Truls Raastad, and Jorunn Sundgot-Borgen Abstract: Lean body mass (LBM) is important in power-related sports. In athletes with heavy training loads and competitions, it may be difficult to increase and maintain LBM during the season. The purpose of this study was to evaluate the long-term effects on body composition after an 8 12 week weight-gain period with or without nutritional guidance. Twentyone elite athletes where randomized to 1 of 2 groups: the nutritional counselling group (NCG; n = 12, 18.5 ± 1.7 y, 67.8 ± 7.4 kg) and the ad libitum group (; n = 9, 19.6 ± 2.7 y, 74.2 ± 5.7 kg). The NCG followed a meal plan that provided a surplus of 506 ± 84 kcal day 1, whereas the had an ad libitum energy intake (EI) during the strength-training (4 sessions per week) intervention. Body mass (BM) and body composition were measured pre- and postintervention, and 6 and 12 months after the intervention. EI in the NCG was normalized after 12 months, whereas EI in the was unchanged during or after the intervention. BM increased more in the NCG than in the during the intervention (4.3% ± 0.9% vs. 1.0% ± 0.6%) and after 12 months (6.0% ± 0.9% vs. 1.8% ± 0.7%). LBM increased in the NCG during the intervention (2.8% ± 0.5%) and after 12 months (4.4% ± 1.0%), whereas LBM in the was unchanged. The NCG managed to maintain and increase BM and LBM after the intervention period. Hence, the focus on nutritional guidance, in addition to strength training, seems to be preferable for obtaining the long-term effect of weight gain in athletes. Key words: energy intake, strength training, hypertrophy, lean body mass. Résumé : La masse maigre (LBM) est un important facteur dans les sports de puissance. Chez les athlètes ayant de lourdes charges d entraînement et des compétitions, il semble difficile d augmenter et de maintenir la LBM tout au long de la saison. Cette étude se propose d évaluer sur une longue période la composition corporelle consécutive à un gain de masse corporelle en 8 à 12 semaines, et ce, avec ou sans conseils nutritionnels. Vingt et un athlètes d élite sont répartis aléatoirement en deux groupes, l un incluant des conseils nutritionnels (NCG, n = 12, 18,5 ± 1,7 ans, 67,8 ± 7,4 kg) et l autre, y allant ad libitum (, n = 9, 19,6 ± 2,7 ans, 74,2 ± 5,7 kg). Le groupe NCG s en tient à un plan de repas comprenant un surplus de 506 ± 84 kcal jour 1 tandis que le groupe y va ad libitum sur le plan de l apport d énergie (EI) au cours de la phase d entraînement à la force constituée de 4 séances par semaine. On évalue la masse corporelle (BM) et la composition corporelle avant la phase d entraînement à la force, immédiatement après, puis 6 et 12 mois plus tard. Chez le groupe NCG, l apport d énergie est de retour aux valeurs normales au 12 e mois tandis que chez le groupe, l apport d énergie ne varie pas durant et après la phase d entraînement à la force. Chez le groupe NCG, la BM augmente plus que chez le groupe, et ce, après la phase d entraînement à la force (4,3 ± 0,9 % vs. 1,0 ± 0,6 %) et 12 mois plus tard (6,0 ± 0,9 % vs. 1,8 ± 0,7 %). Chez le groupe NCG, la LBM est plus importante après la phase d entraînement à la force (2,8 ± 0,5 %) et 12 mois plus tard (4,4 ±1,0 %); chez le groupe, la LBM demeure stable. Le groupe NCG réussit à maintenir sa BM et sa LBM et à l augmenter après la phase d entraînement à la force. En plus d enregistrer des gains sur le plan de la force musculaire, les conseils nutritionnels servent aussi à favoriser à long terme la prise de poids chez les athlètes. Mots clés : apport d énergie, entraînement à la force, hypertrophie, masse maigre. [Traduit par la Rédaction] Introduction Muscle mass is an important determinant of performance in sports that depend on high muscle strength or power. Thus, achieving and maintaining increases in lean body mass (LBM) in the off-season and during the season is an important goal for many athletes (Walberg-Rankin 2002). However, many athletes find these goals challenging to achieve in a busy training schedule. A typical scenario is that the athlete manages to increase LBM in the off-season but fails to maintain LBM during the competitive season, which may lead to impaired performance at the end of the season. This may be due to suboptimal or lack of strength training between competitions, and difficulties maintaining a sufficient energy intake because of time constraints and practical implications. Received 30 November Accepted 11 April Published at on 18 August I. Garthe. Norwegian School of Sport Sciences, Oslo, Norway; The Norwegian Olympic Sports Center, Oslo, Norway. T. Raastad and J. Sundgot-Borgen. Norwegian School of Sport Sciences, Oslo, Norway. Corresponding author: Ina Garthe ( ina.garthe@olympiatoppen.no). Appl. Physiol. Nutr. Metab. 36: (2011) doi: /h11-051

2 548 Appl. Physiol. Nutr. Metab. Vol. 36, 2011 There are few studies of lean mass gain in elite athletes and, to our knowledge, no study has evaluated the long-term effect of guided strategies of this nature. It is known that positive energy balance, in combination with strength training, is effective in terms of gaining muscle mass (Rozenek et al. 2002; Kreider et al. 1996). However, athletes with a long history of heavy strength training may have less capacity to increase LBM and improve strength-related performance (American College of Sports Medicine 2009). In addition, the potential for muscle growth depends on an athlete s genetics (American College of Sports Medicine 2009). Individuals show different responses to the same intervention (Bouchard et al. 1990; Dériaz et al. 1993; Forbes et al. 1986), and studies on the long-term effect of body mass (BM) loss interventions in sedentary overweight participants illustrate the difficulty in maintaining changes in body composition over time (Wing and Phelan 2005). For the sedentary overweight population, specific approaches associated with long-term weight loss have been identified; namely, high levels of physical activity (1 h per day), eating a lowcalorie, low-fat diet, eating breakfast regularly, self-monitoring weight, and maintaining a consistent eating pattern on weekdays and weekend days (Wing and Phelan 2005). To our knowledge, factors that assist long-term gain in LBM are unknown, and there is a lack of data on the long-term changes in body composition overall in the athletic population. Therefore, the aim of this study was to examine whether a controlled positive energy balance, through nutritional counselling, would have better long-term outcomes in managing desirable changes in body composition than ad libitum intake during an 8- to 12-week heavy strength-training period. We hypothesized that the athletes in the guided intervention group would have greater gains in BM and LBM 12 months after the intervention than the ad libitum group (). Materials and methods Participants Forty-seven elite athletes (17 31 y) were recruited for this study, with 39 athletes completing the intervention and 21 completing the 6- and 12-month follow-up tests (Fig. 1). An elite athlete was defined as one who qualified for the Norwegian national team at the junior or senior level, or who was a member of a recruiting squad for that team (students at the Norwegian top-level Sports College). The reasons given for dropping out were as follows: the project was too time consuming (n = 3), the strength-training program interfered with sport-specific training techniques (n = 1), the athletes had moved on to play for other clubs or hockey leagues (n = 10), the athlete was not accessible (n = 2), and the athlete was injured (n = 10) (Fig. 1). The athletes were recruited by invitation from the Department of Sports Nutrition at the Norwegian Olympic Sport Center when they contacted the center to get assistance with weight gain, or by invitation letters to sport federations. The following sports were represented in the final sample in the nutritional counselling group (NCG): rowing (n = 1), soccer (n = 2), volleyball (n = 1), tae kwondo (n = 1), skating (n = 2), and ice hockey (n = 5). In the, the sports represented were kayaking (n = 1), soccer (n = 2), skating (n = 2), and ice hockey (n = 4). Ratios of males to females were 83% to 17% in the NCG and 78% to 22% in the. The physical and anthropometrical characteristics of the athletes are shown in Table 1. The secretary general of each sport federation, the national team coach, and the head of the healthcare team for each of the national teams received detailed written information about the aims and procedures of the study. The athletes were fully informed about the purpose and experimental procedures before written consent was obtained. The study was conducted according to the Declaration of Helsinki, and approved by the Data Inspectorate and the Regional Ethic Committee of Southern Norway. Permission to conduct the study was provided by the Norwegian Olympic Committee and the Norwegian Confederation of Sports. Experimental design The athletes were screened and block randomized into 1 of 2 groups: NCG or. All athletes followed an 8- to 12- week period of targeted BM gain. Athletes in both groups were aiming for a weekly gain of 0.7% of total BM, with the emphasis on increasing LBM and avoiding large gains in fat mass (FM). The length of the intervention period for each subject depended on the athlete s goal. For example, for a 70 kg athlete with a weekly goal of gaining 0.5 kg and an overall goal of increasing BM by 5 kg, an intervention period of 10 weeks would be required. The athletes in the NCG received nutritional counselling once a week during the intervention, whereas the athletes in the did not receive any nutrition counselling. The counselling included basic nutrition, sports physiology, and possible adjustments in the dietary plan, depending on progress. All athletes undertook 4 strength-training sessions per week. After the intervention period, the athletes received 1 nutrition counselling session and 1 exercise counselling session to stabilize their new BM and body composition. Preparticipation screening The purpose of the screening was to evaluate whether the athletes met the inclusion criteria. The inclusion criteria were as follows: elite athletic status, age from 17 to 35 years, and a desired weight gain of 4% of BM. The main exclusion criteria were as follows: diseases and conditions that are known to affect metabolic functions in muscle, the use of pharmaceuticals that may affect any of the measurements, and pregnancy. The screening was a clinical interview and medical examination, according to the standard for preseason health evaluation at the Norwegian Olympic Sports Center. Athletes were screened for disordered eating and eating disorders with the Eating Disorder Examination (Garner 1991) and a medical examination by a sports medicine physician. Athletes under the age of 18 were screened by an orthopedic doctor and evaluated to make sure that skeletal growth was terminated. Intervention Diet Diet registrations were obtained using a 4-day weighed food record, which was analyzed by the national food database, Mat På Data (version 5.0. LKH, Norway). The athletes maintained a stable BM during the week of diet

3 Garthe et al. 549 Fig. 1. Flow chart of study participants., ad libitum group; NCG, nutritional counselling group. Drop-outs n=1 Drop-outs n=9 NCG n=22 Completed intervention n=21 Table 1. Baseline data, presented as mean ± SD. Completed 6 and 12 months n=12 NCG (n = 12) (n =9) Age (y) 18.5± ±2.7 Height (cm) 178.0± ±7.0 Body mass (kg) 67.8± ±5.7* Lean body mass (kg) 58.5± ±7.2 Fat mass (kg) 7.2± ±4.4* Total body fat (%) 11.0± ±6.0 Experience as athletes (y) 11.2± ±2.4 Training (h per wk) 17.7± ±6.0 Strength training last season (h per wk) 3.8± ±0.3 *Significantly different between groups. registration. The record served as a basis for the development of each athlete s individualized diet plan in the NCG, promoting a weekly gain of 0.7% of total BM. The macronutrient distribution of the diet was designed to have a protein intake corresponding to 2 g kg BM 1, a carbohydrate intake corresponding to 5 7 g kg BM 1, and 25% 30% fat. The focus was on energy- and nutrient-dense foods, as well as on high food variety and a frequent meal pattern, to ensure energy intake every third hour, corresponding to 5 7 meals per day. The dietary plan was tailored to meet each athlete s specific needs, and was designed to be as optimal as possible for both health and athletic performance. All NCG athletes ingested a recovery meal, containing carbohydrates (40 50 g) and protein of high biological value (15 20 g), in the 30 min after training sessions, and a balanced meal 1 2 h after training to optimize recovery (American Dietetic Association 2009; Tipton and Wolfe 2004). The athletes were encouraged to use a food scale to ensure correct portion sizes. If the athletes were unable to follow the dietary plan during Included=47 Randomized n=25 Completed intervention n=18 Completed 6 and 12 months n=9 Drop-outs n=7 Drop-outs n=9 the week, they were instructed to write down any deviance from the plan. By comparison, athletes in the did not get feedback on their diet registration before they completed the intervention. athletes were instructed to eat ad libitum during the intervention period, with the goal of gaining 0.7% of their BM each week. All the athletes received 1 nutritional counselling session in the first month after the intervention to establish weight maintenance. A 24-h recall was done mid- and post-test to monitor changes in the nutritional variables during the follow-up period. The athletes were not allowed to use creatine supplements during the6 weeks immediately before study inclusion, and they did not take any supplements other than those given by the nutritionist during the intervention (e.g., if blood samples indicated any other specific micronutrient needs, these vitamins or minerals were provided to the athletes and biochemical changes were monitored). Athletes in both groups had free access to sports products, such as sports drinks and recovery shakes (30% protein and 70% carbohydrate drink) from Maxim International Ishøj, Denmark). There were no supplement restrictions after the intervention. Nutritional counselling NCG athletes received nutritional counselling once a week for the duration of the intervention. The counselling covered basic nutrition, sports physiology, and possible adjustments in the dietary plan, depending on progress. athletes did not receive any nutritional counselling before or during the intervention. Training The intervention started in the off-season for all athletes a period of basic training in which it would be possible to add additional training without interfering with competition or travel. All athletes continued their sport-specific training

4 550 Appl. Physiol. Nutr. Metab. Vol. 36, 2011 schedule (16.7 ± 5.4 h per week, presented as a mean of the training during the previous year). In addition, 4 strengthtraining sessions per week were included to emphasize muscle strength and hypertrophy. The strength-training program was a 2-split periodized program. Each muscle group was exercised twice a week with 2 exercises: a main exercise and one for the isolation of the specific muscle group. The athletes followed a repetition maximum (RM) regimen for the first 4 weeks, a RM for the next period, and a RM for the final 4 weeks. For the athletes who participated for fewer than 10 weeks (n = 14), the program was adjusted with shorter periods. The rest period between sets lasted 1 3 min. Athletes were supervised once per week during training at the Olympic Sports Center to ensure correct technique and adequate progress. A computerized exercise diary was recorded throughout the intervention period, supervised by the personal trainer. After the intervention, athletes trained as usual with no interference from the researchers. Because strength-training experience is an important variable that affects the expected increase in LBM during a period of heavy strength training (American College of Sports Medicine 2009), we screened the athletes for their strength-training background. Experimental assessments All tests were conducted by the same test team at both preand postintervention, and the test day was standardized. Athletes were not allowed to perform heavy training 48 h prior to testing. Body mass BM was measured in the fasted state, after emptying the bladder, with a balance scale (SECA model 708, Seca Ltd., Birmingham, UK) to the nearest 100 g on the test day in the morning between 0800 and 0900 hours. During the intervention period, athletes used their own scales to monitor BM, since their weekly meetings with the nutritionist were at different times during the day and weight fluctuates, depending on food and liquid intake. They were instructed to weigh themselves without clothes and with an empty bladder immediately after waking up and before breakfast. Dual-energy X-ray absorptiometry FM, % body fat, and LBM were measured with dual-energy X-ray absorptiometry DXA ( Lunar Prodigy, GE Medical Systems, Madison, Wisc.) by a trained technician. The DXA system was calibrated on the day of testing, and the test was conducted in a fasted state between 0830 and 1000 hours. The coefficient of variation in DXA total body scan for repeated measurements was 3.0% for FM and 0.7% for LBM. Statistical analyses Data are presented as mean ± SD for pre- and post-test measurements, and mean ± SE for changes within and between groups. Graphpad Prism software (version 5.0) and SPSS (version 15) were used for statistical analyses. The changes from preintervention to 12-month follow-up were analyzed with repeated-measures analyses of variance (ANOVAs) within groups, and with 2-way repeated-measures ANOVAs between groups. Significant interactions were corrected with the Bonferroni post hoc test. p values below 0.05 were considered statistically significant. Results The mean time spent in intervention was 9.9 ± 1.8 weeks for the NCG and 9.8 ± 1.4 weeks for the. There were no significant differences between groups in any of the baseline measurements, except for the significantly higher BM and FM in the (Table 1). Diet Energy intake for the NCG was higher during the intervention than at baseline (2821 ± 1010 vs ± 761 kcal per day), but had returned to baseline at 6- and 12-month followups (Table 2). Although the had the same goals of BM gain, energy intake did not change throughout the study (Table 3). Consequently, the intake of macronutrients was higher for the NCG than for the during the intervention, but no significant differences were seen at 6- and 12-month follow-ups (Tables 2 and 3). Body composition The predetermined BM goal for the NCG and the was 4.7 ± 0.8 and 5.1 ± 0.8, respectively, with a weekly gain of 0.7% of initial BM. BM increased more in the NCG than during the intervention (4.3% ± 0.9% vs. 1.0% ± 0.6%, p = 0.01) (Fig. 2). After the intervention, the BM continued to increase in the NCG, and was significantly higher than in the at 6- and 12-month follow-ups. A larger increase in FM in the NCG (17.4% ± 5.1%) than in the (5.6% ± 3.1%) was observed during the intervention (p < 0.05) and at 6-month follow-up, but was not different at 12- month follow-up (Fig. 3). LBM increased in the NCG during the intervention by 2.8% ± 0.5%, continued to increase at 6- month follow-up, and was significantly higher than the at 12-month follow-up (Fig. 4). When looking at the distribution of LBM gains, 67% of the increase during the intervention was due to a gain in the upper body. Between the 6- and 12-month follow-ups, the increase in LBM was only contributed to by gains in the legs. Only 2 females were included in each group; therefore, tests for possible gender differences were not performed. Excluding the female athletes from the analyses did not change the results significantly. Training Athletes in the NCG and the reported training 17.7 ± 6.8 h per week and 16.0 ± 6.0 h per week, which included 3.8 ± 0.5 h per week and 3.9 ± 0.3 h per week, respectively, on strength training during the year before entering the study. They reported spending between 6 7 h per week on strength training during the intervention, and reported that they went back to baseline hours spent in strength training at 6-month follow-up. At 12-month follow-up, they reported spending 4.3 ± 1.7 h per week in strength training. Compliers vs. noncompliers The predetermined goal for BM gain in the NCG was 4.7 ± 0.8 kg and in the was 5.1 ± 0.8 kg, with a weekly gain of 0.7% of initial BM. The long-term goal for athletes in the NCG and the was to maintain

5 Garthe et al. 551 Table 2. Energy and nutrition variables in the NCG (mean ± SD). Diet registration Meal plan 6-mo follow-up 12-mo follow-up Energy intake (kcal) ± ±561.0* ± ±982.0 Protein (g kg 1 body weight) 1.7± ±0.43* 1.7± ±0.5 Carbohydrate (g kg 1 body weight) 5.3± ±1.5* 4.7± ±1.3 Fat (E%) 29.2± ±2.8* 33.4± ±5.3 Note: E%, percent of total energy intake. *Significantly different within groups. Table 3. Energy and nutrition variables in the (mean ± SD). Diet registration 24-h recall 6-mo follow-up 12-mo follow-up Energy intake (kcal) ± ± ± ±972.0 Protein (g kg 1 body weight) 1.6± ±0.3* 1.8± ±0.4 Carbohydrate (g kg 1 body weight) 5.3± ±2.3* 5.1± ±1.4 Fat (E%) 30.0± ±3.8* 29.8± ±4.7 Note: E%, percent of total energy intake. *Significantly different between groups. Fig. 2. Changes in body mass in the NCG and the from preintervention to 12-month follow-up. Data are presented as mean ± SE. *p < 0.05, vs. preintervention, p < 0.05 for between-group difference. Change (%) 8 NCG Pre * * Post 6months 12 months (n = 4 vs. 1) or even increase (n = 8 vs. 8) BM during the season. We included all participants in our analyses, according to the intention-to-treat principle. Seven of the athletes in the NCG (58%) did not accomplish their BM goals (with a cut-off value in weekly BM gain of 0.5 kg) during the intervention, but all the athletes in the NCG managed to maintain or increase BM, according to their goals, at 12-month followup. No significant differences were found between compliers and noncompliers in training hours, baseline values in LBM, or strength-training experience. Although athletes in the did not have any meal plans or nutritional guidance, their goal was also a weekly gain of 0.7% of BM. However, no athletes in the accomplished their goal during the intervention. After 12 months, 3 (33%) of the athletes in the had a lower BM, whereas 6 had maintained or increased their BM. * Fig. 3. Changes in fat mass in the NCG and the from preintervention to 12-month follow-up. Data are presented as mean ± SE. p < 0.05 for between-group difference. Change (%) Change (%) 30 NCG Pre 6 NCG Pre Post Post 6 months 6months 12 months Fig. 4. Changes in lean body mass in the NCG andthe from preintervention to 12-month follow-up. Data are presented as mean ± SE. *p < 0.05 vs. preintervention, p < 0.05 for betweengroup difference. * 12 months

6 552 Appl. Physiol. Nutr. Metab. Vol. 36, 2011 Discussion The aim of this study was to compare the effects of nutritional counselling and ad libitum dietary intake on changes in body composition 6 and 12 months after a focused strengthtraining period in elite athletes. We hypothesized that the athletes in the NCG would maintain BM and LBM to a greater extent than those in the 6 and 12 months after the intervention. In accordance with our hypothesis, athletes in the NCG had significantly higher BM and LBM than those in the after 12 months. Diet Both under-reporting and undereating are common measurement errors in self-reported dietary intake; this has to be taken into consideration (Magkos and Yannakoulia 2003). We chose a 4-day weighed food registration to minimize the burden, poor compliance, and alteration of the subject s usual intake. The calculated energy surplus in the diet plan for the NCG was 506 ± 84 kcal day 1. The mean carbohydrate intake during intervention was 7.2 ± 1.5 g kg 1 for the NCG and 5.0 ± 2.3 g kg 1 for the, and within the recommended carbohydrate intake for athletes (American Dietetic Association 2009). The mean protein intake was 2.5 ± 0.4 g kg 1 for the NCG and 1.8 ± 0.3 g kg 1 for the. Protein intake for the NCG was slightly higher than the recommended protein intake for athletes (American Dietetic Association 2009; Tipton and Wolfe 2004). Adequate protein intake was considered important to ensure a sufficient amino acid supply to the muscles and to enhance recovery. The meal plans for the NCG during the intervention were based on the dietary registrations and nutrient intake recommendations, and the athletes were involved in the development of their own meal plan. This included choice of food and drinks and timing of intake. We considered individual involvement in planning to be crucial for the compliance and motivation of the athletes during the intervention, and to make it easier to follow after the intervention to prevent weight loss. If the athletes were unable to follow the dietary plan during the week, they were instructed to write down any deviance from the plan. This was discussed during the weekly counselling sessions. There was no control for food intake during the week other than the counselling and weight report the during intervention. Although athletes in the NCG were closely monitored, 7 did not accomplish their goals of mass gain during the intervention. However, all athletes in the NCG managed to maintain or increase BM 12 months after intervention, and were more successful than those in the, in which no athlete accomplished their mass gain goal during the intervention and only 6 athletes managed to maintain or increase their BM after 12 months. All athletes had tried to gain mass at least once during their athletic career, and reported that increasing mass and maintaining mass gain, in particular, during the season were a challenge. It is important to recognize the genetic factors and the challenges associated with individual metabolic response to overfeeding, making weight gain more difficult for some individuals (Bouchard et al. 1990; Leibel et al. 1995; Weyer et al. 2000). Oral feedback from the athletes in the NCG indicated that they considered the meal plan and nutritional guidance to be very helpful during the intervention, and that the maintenance meal plan helped them to continue the process after the intervention. All athletes in the NCG reported that they had followed the meal plan to some extent (e.g., meal frequency, recovery meals, food choices) for 6 to 12 months. Feedback from athletes in the indicated that they found it challenging to increase energy intake, mostly because of practical implications, such as planning meals and finding time to eat, but also because of the insecurity about food choices and the amount of food intake by some athletes who tried to avoid gaining excess body fat during and after the intervention. Body composition The increase in LBM contributed to 57% of the gain in BM in the NCG; body composition changed in the, but BM was relatively stable during the intervention. It has been suggested that an increase in BM of kg per week should be a realistic goal if it is related to a gain in LBM (American College of Sports Medicine 2009; Houston 1999; Rozenek et al. 2002). Furthermore, it has been suggested that the athlete should have a positive energy balance of kcal per day to reach this goal (Houston 1999; Walberg-Rankin 2002). However, there is a question of whether this is realistic in elite athletes. The finding that athletes in the NCG did not accomplish even greater gains in total LBM, despite an energy surplus corresponding to 500 kcal, may have several explanations. First, all athletes had some strength-training experience; power and strength were important factors for their sport-specific performance. Thus, we could not expect large increases in LBM after 8 12 weeks of heavy strength training. Another reason for not accomplishing greater gains in LBM in our study may be that athletes in both groups continued their sport-specific training during the intervention. Although the intervention period was completed off-season and the athletes emphasized strength training during the period, some technical and endurance training to maintain sport-specific skills was necessary. Combining strength training with endurance training can suppress some of the strength-training adaptation, thereby limiting changes in skeletal muscle cross-sectional area (Hawley 2009). The relatively large increase in FM seen in the NCG after the intervention may be problematic for some athletes during a mass gain period for a variety of reasons, ranging from hindering sport-specific performance to not fitting the stereotype of the lean and muscular athlete. Our results indicate that experienced strength-trained athletes can only increase LBM to a limited extent, and that a short period of energy surplus in these athletes may cause gains in FM as well as in LBM. However, the data indicate that it is easier to increase LBM without increasing FM when the weight gain period is of longer duration. The athletes in the NCG managed to increase BM and LBM while decreasing FM. That is remarkable, since the athletes participated in less strength training and more sports-specific training and competitions during the 6 and 12 months after the intervention. Although there were no significant differences between the mean ages in the 2 groups, there were more young athletes in the NCG than in the (7 vs. 3 athletes under the age of 18 years), which may have influenced the results. Athletes under the age of 18 years were screened by an orthopedic doctor and eval-

7 Garthe et al. 553 uated to make sure that skeletal growth was terminated. About 50% of adult body weight is gained during adolescence, and peak weight velocity occurs at about the same time as peak height velocity (Rogol et al. 2000). However, the rate of weight gain decelerates in a manner similar to height velocity during the later stages of pubertal development (Rogol et al. 2000), so it is unclear how many of the changes seen in the 10 athletes aged 17 or 18 years were due to biological growth during the 12-month period. Furthermore, we found a significant correlation between age and mass gain at the 12-month follow-up (r = 0.45, p = 0.04). This indicates that the great discrepancy in the results in mass gain between groups may partly be explained by the higher number of young athletes in the NCG. However, during the first 6 months of the season with frequent competitions, both groups followed the same trend, tending to slightly reduce LBM. After 6 months, athletes in the NCG started to increase LBM, whereas those in the continued to decrease LBM. This indicates that age is not the only explanation for the discrepancy between groups. If that had been the case, LBM would probably have followed a different pattern in the NCG than in the during the first 6 months. Feedback from athletes indicates that they initiated an intervention period, as learned during the study intervention, as the competitive season wound down. It is interesting to see that athletes in the NCG had increased LBM significantly at the 6-month follow-up, without nutritional guidance, other than what they received during the intervention. It is also interesting to see that 100% of the LBM gained in the NCG between the 6- and 12-month follow-ups was due to gains in LBM in the lower body (legs), not the upper body, as seen during the intervention. The athletes did not report any specific changes in their strength-training program between the 6- and 12-month follow-ups, but all athletes from the NCG reported that they partly followed the intervention meal plan. Compliers Compared with the athletes in the, none of whom accomplished their mass gain goal, the athletes in the NCG were more successful in reaching their mass gain goal. However, we had expected a higher number of athletes in the NCG to succeed. It might bethat the noncompliers in the NCG were actually nonresponders to the intervention, owing to counter regulatory mechanisms (i.e., increased metabolism or other mechanisms decreasing food efficiency) (Bouchard et al. 1990; Leibel et al. 1995; Weyer et al. 2000). The number of dropouts was 10 in the NCG and 16 in the. Even though both groups had a weekly meeting with a personal strength trainer during the intervention, those in the NCG received additional counselling on nutrition during the intervention, which may have contributed to increased commitment to the project during and after the intervention. Conclusion We found that those in the NCG had significantly higher gains in BM and LBM at the 12-month follow-up. Thus, athletes who received nutritional counselling during a mass gain period were more successful in reaching their physique goals and in maintaining the positive changes in BM and LBM than athletes who had an ad libitum energy intake during the intervention period. However, the results must be interpreted with caution because there was a correlation between age and changes in BM at 12-month follow-up, and there were more athletes under 18 years in the NCG. Acknowledgements The authors would like to thank the athletes who participated in the study for their time and dedication. 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