This systematic review followed the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines for searching, selecting, collecting, and analyzing data13. We identified studies through PubMed, Science Direct, Web of Science, and Embase electronic databases, published until November 2022. Our review focused solely on published articles, and we did not contact authors regarding unpublished articles or results. The search items included a combination of medical subject headings (MeSH terms) and free-text words, consisting of the following: (1) DLW, or doubly labeled water; (2) total energy expenditure, total daily energy expenditure, TEE, or TDEE; and (3) sports, athletes, or players.

The inclusion criteria for the review were as follows: (1) original research articles, (2) studies that measured TEE using the DLW method, (3) participants who were collision sports athletes of either sex, and (4) studies published in English. The exclusion criteria were (1) studies that included players in non-collision team sports and (2) studies that did not assess TEE using the DLW method.

Two independent, experienced, systematic reviewers performed the search and study selection. Disagreements between reviewers were resolved through discussion. Additionally, the titles and abstracts of the studies were searched and screened, and during the second screening step, the two independent reviewers evaluated the full texts of the articles for inclusion.

Two authors independently extracted the data. A second reviewer double-checked the extracted data and resolved discrepancies through a consensus meeting discussion. The characteristics of the extracted study data included the year of publication, number of participants, participant characteristics (age, sex, weight, height, FFM, team standards, and position), measurement period, training information during measurement, and TEE. However, only studies using the DLW technique were selected as the TEE evaluation method, and those using convenient prediction methods such as accelerometers and heart rates were excluded. All data were expressed as kilocalories (kcal), and data published in kilojoules (kJ) or megajoules (MJ) were converted to kcal.

After searching the four databases, 1,497 studies were identified. After reviewing the title and abstracts of the databases, 1,156 were excluded. After eliminating duplicates and review articles, 327 studies were excluded; after excluding two wherein DLW values were not presented and one study with data duplication, 13 studies were included in the final analysis. Thirteen studies involving approximately 200 individuals published between 2002 and 2022 were included in the final analysis. Most included studies were published after 2010, except for one [4].

The participants of this review were male and female rugby, soccer, and basketball players (12-27 years). However, in the search, no study had measured TEE using the DLW method for ice hockey or field hockey players, which are also collision sports. The 13 studies consisted of four rugby [5,9,11,14], six soccer [4,15-19], and three basketball [10,20,21] players. All four studies included male rugby players [5,9,11,14]. One of the six studies evaluated the TEE of female soccer players [15]. The three basketball player studies were conducted on males and females [10,20,21]. Two of the four rugby studies involved young players [9,11], and one included youngsters and adults [5]. However, the rugby study did not report age data [14]. In soccer, only one study evaluated adolescent players [16], whereas the other five studies evaluated adult players [4,15,17-19]. All three basketball studies were conducted on junior players [10,20,21].

The TEE measured using DLW of male rugby players was 4484.23 kcal/day (range: 3862.3-5783.9 kcal/day), for male soccer players was 3250.1 kcal/day (range: 2859-3586 kcal/day), and for male basketball players was 4530.5 kcal/day (range: 4006-4921 kcal/day). Our data demonstrated significant differences in TEE between different team sports, with basketball and rugby players presenting an absolute TEE of ~1500 kcal/day, which was greater than that of soccer players. These differences in TEE according to the sport are likely because of differences in body composition or training load, although the amount of training could not be quantified. Adolescent rugby players (age=15.6 y, weight=85.4 kg, height=182.1 cm, FFM=66.4 kg, TEE=4010 kcal/day)(5)W and basketball players (age=17.0 y, weight=80.9 kg, height=192.5 cm, FFM=72.5 kg, TEE=4621.7 kcal/day)21 have higher FFM and are taller and heavier than soccer players (age=17.5 y, weight=73.1 kg, height=181.2 cm, FFM=57.2 kg, TEE=3586 kcal/day) [16]. Our review revealed that the TEE showed high fluctuations according to the amount of training, period, sex, and age. Hannon et al. reported a significant positive relationship between TEE and stature (r² =0.41; p <0.01), body weight (r² = 0.65; p < 0.01), FFM (r² =0.65; p < 0.01), RMR (r² =0.56; p < 0.01), and activity energy expenditure (r² = 0.79; p < 0.01) in male adolescent soccer players from the English Premier League (EPL) Academy aged U12/13 to U18 [16].

Collision-related muscle damage requires considerable energy to restore the body [9]. Costello et al. reported that TEE, including collision intervention (10 one-on-one tackles and 10 one-on-one hit-ups), was significantly higher than TEE of non-collision groups (matched for kinematic demands) in young professional rugby players (4542.5 ± 796.0 kcal/day vs. 4316.5 ± 810.8 kcal/day; p < 0.05) [9]. Although the collision and non-collision groups performed the same training schedule (total distance: 9513 ± 640 m vs. 9818 ± 439 m; p = 0.105), there was a statistically significant difference in TEE. Sufficient energy intake strategies are needed because the high energy cost of collisions evidenced in interventions is likely modest compared to what athletes are exposed to [9].

Morehen et al. assessed the TEE of professional RL players over 2 consecutive weeks with the same training schedule each week (1 competitive game day, 4 training days per week); the results showed that TEE increased significantly from Week 1 to Week 2 (4278.2 ± 501.9 kcal/day vs. 5783.9 ± 812.6 kcal/day, respectively) [14]. Similar results were reported in a study of U12/13 soccer players, where the TEE was higher in Week 2 than that in Week 1 (3122 ± 364 kcal/day vs. 2702 ± 255 kcal/day; p < 0.05) [16]. Although there was no significant difference in duration and total distance during each week of training, the TEE was higher in Week 2, despite the average speed in week 1 being significantly higher than that in week 2 [16]. The TEE of Week 2 was reported higher than Week 1 because the recovery energy of the training and the game of Week 1 might have accumulated in Week 2.

The increased energy cost of collisions during training or competition may be caused by an increase in wholebody protein turnover in response to muscle damage [22]. Our review suggests that professional collision sports players require appropriate energy intake strategies to recover from muscle damage-induced collisions.

A study conducted by Costello et al. showed that the TEE of adolescent professional RL players was higher during the pre-season than that during the in-season (4385.8 ± 726.6 kcal/day vs. 3862.3 ± 184.0 kcal/day; no statistical data) [11]. Since the same five players were used in each period, the difference in TEE was expected to be affected by the amount of training, not body composition. The pre-season training in Costello et al.’s study (14 days) consisted of 10 resistance training sessions and 10 field sessions, while in-season (7 days) consisted of one competitive match, three resistance training sessions, three field sessions, and one captain run [9]. No information was reported on the intensity or duration of the training or matches during the season, but the amount of training may have affected the TEE [11]. Conversely, in the basketball study [10], the TEE of Portuguese junior national basketball players was higher during the competitive period than that during the pre-season (4243.1 ± 937.1 kcal/day vs. 3810 ± 1503.3 kcal/day; p < 0.05). In this systematic review, the difference in TEE by period was expected to be because of the differences in training intensity for each sport. Further research is needed on male soccer players using pre-season data.

In a study on soccer, U18 players of the Category 1 top-tier EPL soccer academy were found to have a TEE (3586 ± 487 kcal/day; range: 2542-5172 kcal/day), which was higher than both the U15 players (3029 ± 262 kcal/day; range: 2738-3726 kcal/day) and U12/13 players (2859 ± 265 kcal/day; range: 2275-3903 kcal/day) [16]. Hannon et al. reported that the differences in TEE were likely because of a combination of differences in anthropometric profiles, RMR, and physical loading (training and match). The U18 players had higher RMR and anthropometric profiles (stature, body mass, and FFM) than those of the U12/13 and U15 players. In addition, U18 and U15 players completed more distance and minutes of activity than those of U12/U13 players [16].

The TEE of the U12/13 and U15 age groups was found to be comparable to that of adult Premier League players [16-18]. However, several U18 players (3845 ± 826 kcal/day) displayed TEE values that exceeded those of adult players (goalkeeper: 2894 kcal/day; other positions: 3566 ± 585 kcal/day), despite having approximately 7 kg less FFM [16-18]. These data demonstrated that TEE progressively increased as players transitioned through the academic pathway, likely because of the influence of growth and maturation on key anthropometric parameters and increased physical loading.

In a rugby study (5), U24 players (RL, RU) presented with a TEE (4761 ± 1523 kcal/day), higher than that of U16 players (4010 ± 744 kcal/day). U24 players (Weight=98.3 ± 4.8 kg, Height=184.7 ± 2.5 cm, FFM=82.1 ± 4.8 kg; light training 8-9 days, heavy training 1 day, rugby match 0-2 days, rest 4 days) of RL were taller and heavier than U16 players (Weight=79.3 ± 17.1 kg, Height=180.8 ± 7.0 cm, FFM=62.2 ± 10.6 kg; light training 4 days, heavy training 3 days, rugby match 0-2 days, rest 8 days) and their training and match load was different. The differences in TEE between U24 and U16 are also likely because of a combination of differences in the anthropometric profile, RMR, and training and matching loads.

However, no study has yet evaluated the TEE of adult basketball players. Therefore, to evaluate the players’ TEE accurately based on age, a study is required to compare the TEE of adult players with that of growing players with similar training levels.

In our systematic review, we analyzed four TEE studies in which female team sports players consisted of three young basketball players [10,20,21] and one adult soccer player [14]. In both sports, female players had lower TEE than male players. In a study by Morehen et al., the TEE of female soccer players during an international training camp was 2693 ± 432 kcal/day. Among basketball players [21], female players had a lower TEE (3493.8 ± 241.9 kcal/day) than that of male players (4621.7 ± 681.4 kcal/day), despite having the same training schedule. The difference in TEE between male and female players is likely because of differences in the anthropometric profile, RMR, and physical load. Female athletes were shorter, lighter, and had lower RMR than male athletes.

When energy intake is insufficient to meet the TEE from high-intensity training, female athletes may experience energy deficiency leading to conditions such as amenorrhea and osteoporosis, collectively known as the female athlete triad [23,24]. To address problems associated with the female athlete triad, nutritional strategies corresponding to TEE should be established to balance energy intake [25]. Further research is required to identify the TEE of female team sports players.

Brinkmans et al. evaluated differences in TEE among Dutch premier league soccer players based on their positions. They found that goalkeepers had significantly lower TEE kcal/kg than midfielders during the season (37.6 ± 2.9 kcal/kg vs. 44.4 ± 3.2 kcal/kg; p = 0.004) because goalkeepers have lower training and match loads compared to field positions [19]. In addition, Anderson et al. showed that the TEE of EPL professional soccer players differed between goalkeepers [17] and players in other positions [18] (center forward, wide defender, wide midfielder, central defending midfielder, central attacking midfielder, and central defender) in the season (2894 kcal/day vs. 3566 kcal/day).

This study had several limitations. First, the number of studies and participants included was small because of the high cost of isotopes and the scarcity of experts in the DLW technique. Second, the training loads of all the studies in our review could not be unified. However, to our knowledge, this is the first systematic review of TEE that focuses on fluctuations in the measurement period, age, position, and sex of players in collision team sports. We only included studies that used the DLW technique, the gold standard method of TEE measurement, for data accuracy. Furthermore, we investigated all studies’ measurement periods and training schedules because TEE in athletes is highly influenced by the season and training volume [12].

This systematic review provides convincing evidence that TEE, measured using the DLW method in collision team sports athletes, including soccer, rugby, and basketball, varies depending on different measurement periods, training loads, and body compositions. Therefore, it is crucial to adopt an individualized and sports-specific approach to energy prescription (energy intake based on energy expenditure) for collision team sports athletes. Such individual approaches should consider various positions, ages, sexes, training, and game loads. This review provides valuable information to improve players’ performance in collision teams.