Table 1.
Prevalence of low energy availability (LEA) in female athletes.
| Author Year | Athlete Population | Duration | LEA (kcal·kg FFM−1·Day−1) Mean ± SD | % Athletes with LEA | Implications of LEA |
|---|---|---|---|---|---|
| Soccer | |||||
| Magee 2020 [18] | NCAA DIII soccer (n = 18, height: 1.67 ± 0.05 m; body mass: 65.3 ± 7.9 kg; body fat %: 24.9 ± 5.6%) | 4 days | All: 27.5 ± 8.9 LEA: 23.0 ± 5.7 Non-LEA: 36.4 ± 7.3 |
The screening tool classified 56.3% of athletes as at risk of LEA. Actual dietary intake identified 67% as LEA. |
N/A |
| Morehen 2021 [31] |
Professional soccer (n = 24; height: 168.1 ± 5.9 cm; weight: 62.1 ± 4.7 kg; body fat%: 20.6 ± 3.7% | 9-day international training camp (4 training days, 1 rest day, 2 travel days, 2 match days) |
(n = 17) 18 ± 9 (range: 2–36) |
<30 kcal·kg FFM−1·day−1, 88% of players | N/A |
| Cherian 2019 [32] | Junior soccer (n = 19; age: 12.2 ± 1.83 years; height: 1.54 ± 0.04 m; weight: 45.1 ± 6.58 kg; body fat%: 23.8 ± 3.46%) | 3-days | All: 27.1 ± 14.44 U12: 31.7 ± 10.10 U16: 24.1 ± 12.32 |
<30 kcal·kg FFM−1·day−1, 58% of girls, of which 37% were Under-16 players. | N/A |
| Moss 2020 [33] | Professional soccer (n = 13) (age: 23.7 ± 3.4 yrs., height: 1.69 ± 0.08 m, body mass: 63.7 ± 7.0 kg) | 5 days during a competitive season | All Days: 35 ± 10 Rest Days: 42 ± 7 Light Days: 35 ± 11 Heavy Day: 29 ± 10 Match Day: 29 ± 16 |
30–45 kcal·kg FFM−1·day−1: 62% LEA (<30 kcal·kg FFM−1·day−1): 23% |
LEA athletes met criteria for low resting metabolic rate. Other biochemical markers were inconclusive. |
| Reed 2013 [19] | NCAA DI soccer (n = 19, age: 19.23 ± 0.3 yrs.; height: 1.66 ± 0.0 m; weight: 60.6 ± 1.4 kg; body fat%: 22.5 ± 1.1% VO2 Max: 57.0 ± 1.0 mL kg(−1) min(−1)) | 3-day monitoring at Pre-, Mid-, and Post-season time points | Mid-season: 35.2 ± 3.7 Post-season: 44.5 ± 3.7 (p = 0.009) |
Low energy availability (<30 kcal·kg FFM−1·day−1) was observed:
|
N/A |
| Track & Field and endurance athletes | |||||
| Heikura 2018 [34] | National/world-class distance runners (n = 25; age: 23–27 years; height: 1.69–1.83 m; body mass: 52.9–70.5 kg) | 7-day monitoring | N/A | LEA: 11/35 (31%) | Amenorrheic and low testosterone athletes had significantly lower sex hormones, triiodothyronine, and bone mineral density, with a ~4.5-fold increased prevalence of bone injuries. |
| Beerman 2020 [16] | NCAA DI cross country (n = 20, age: 20.2 ± 1.7 years; height: 1.77 ± 0.06 m; body mass: 53.7 ± 6.5 kg; body fat %: 23.3 ± 3.6%) | 3-month average | 32.8 ± 16.1 | 30–44 kcal·kg FFM−1·day−1: 7 (41%) <30 kcal·kg FFM−1·day−1: 7 (41%) |
N/A |
| Day 2015 [17] | NCAA DI track and field (n = 25, age: 19.5 ± 1.8 years; height: 1.69 ± 0.05 m; body mass: 61.1 ± 6.9 kg; body fat %: 22.3 ± 3.3%) | 3-day monitoring | 30.8 | <45 kcal·kg FFM−1·day−1: 23 (92%) <30 kcal·kg FFM−1·day−1: 13 (52%) |
N/A |
| Melin 2014 [35] | Endurance athletes (n = 45; age: 26.6 ± 5.4; height: 1.6 9 ± 0.0; weight: 58.7 ± 6.8 kg; body fat %: 20.2 ± 3.4 | 7 consecutive days | All: 38.5 ± 13.9 At risk for LEA: 37.3 ± 13.1 Not at risk: 40.4 ± 15.3 |
At Risk for LEA (LEAF-Q>8): 28/45 (62%) | N/A |
| Schaal 2021 [36] | Healthy distance runners: well-adapted [WA] (age: 29.4 ± 1.6 yrs.; height: 1.65 ± 0.2 m; weight: 57.6 ± 1.6 kg; body fat %: 22.5 ± 1.4) and non-functional overreaching (NFOR) (age: 27.7 ± 2.3 yrs.; height: 1.69 ± 0.2 m; weight: 59.1 ± 3.0 kg; body fat %: 23.5 ± 1.3) | Baseline: 24–35 Days Training Overload: 4 weeks Recovery Phase: 2 weeks |
Baseline: WA:24.4 ± 3.7 NFOR: 30.4 ± 1.9 Training Overload: WA: 26.3 ± 3.8 NFOR: 24.8 ± 2.8 Recovery Phase: WA: 24.3 ± 4.0 NFOR: 26.8 ± 1.6 |
N/A | Suppressed ovarian function. Decreased running performance. |
| Viner 2015 [37] | Competitive cyclists (n = 4; age: 38.4 ± 10.3 yrs.; height: 1.65 ± 0.06 m; weight: 62.8 ± 12.2 kg; body fat %: 24.9 ± 8.4%) | 3 days·month–1, through one cycling season. Records were completed on alternating days each month to represent all days of the week. | Pre-Season: 26.2 ± 14.1 Competition: 25.5 ± 3.1 Off-Season: 23.8 ± 8.9 |
Low energy availability (<30 kcal·kg FFM−1·day−1): 100% at all time points. | N/A |
| Other Sports | |||||
| Zabriskie 2019 [38] | NCAA DII lacrosse (n = 20, age: 20.4 ± 1.8 years; height: 1.68 ± 0.06 m; body mass: 68.8 ± 8.9 kg; body fat %: 27.9 ± 3.0%) | 5 periods, of 4-day monitoring | Off-season: 30.4 ± 11.0 Off-season: 26.2 ± 10.5 Pre-season: 22.9 ± 8.5 In-season: 28.7 ± 9.5 In-season: 28.9 ± 9.2 |
Off-season: 10/20 (50%) Off-season: 12/20 (60%) Pre-season: 15/20 (75%) In-season: 12/20 (60%) In-season: 12/20 (60%) |
Associated with reduced sleep quality and perceived rest. |
| Zanders 2021 [39] | NCAA DII basketball (n = 13; age: 19.8 ± 1.3 yrs.; height: 1.74 ± 0.1 m; weight: 74.6 ± 9.1 kg; body fat %: 27.1 ± 3.2%) | 5 periods, of 4-day monitoring | In-Season (non-conf): 21.8 ± 7.8 In-Season (conf): 22.3 ± 13.7 In-Season (playoffs): 22.5 ± 11.2 Off-Season I: 31.8 ± 8.1 Off-Season II: 30.6 ± 9.5 |
In-Season (non-conf): 10/11 (91%) In-Season (conf): 10/11 (91%) In-Season (playoffs): 5/9 (56%) Off-Season I: 3/10 (30%) Off-season II: 6/11 (55%) |
N/A |
| Braun 2018 [40] | Elite soccer (n = 56; age: 14.8 ± 0.7 yrs.; height: 166 ± 5 m; weight: 56.8 ± 6.1 kg; body fat%: 17.2 ± 3.9%) | 7-day food & activity records | 30.0 ± 7.3 Range: 20.3 to 51.0 |
LEA (i.e., <30 kcal·kg FFM−1·day−1): 53% | N/A |
| Woodruff 2013 [41] | University volleyball (n = 10; age: 20.9 ± 1.4 yrs.; height: 1.77 ± 0.05 m; weight: 75.0 ± 9.7 kg; body fat %: 25.2 ± 6.9%) | 7-day food & activity records | 42.5 | LEA (i.e., <30 kcal·kg FFM−1·day−1): 2/10 (2%) | N/A |
| Schaal 2017 [21] | Synchronized swimming (n = 11; age: 20.4 ± 0.4 yrs.; weight: 58.9 ± 1.8 kg; body fat%: 17.3 ± 0.6%) | 4-day food & activity monitoring period | Baseline: 25.0 ± 3.2 Week 2: 22.3 ± 1.9 Week4: 18.0 ± 2.8 |
LEA (<30 kcal·kg FFM−1·day−1): 11/11 (100%) | Associated with perceived fatigue and endocrine signs of conservation (i.e., increase ghrelin and decrease in leptin). |
| Costa 2018 [22] |
Collegiate female synchronized swimmers (n = 21, 20.4 ± 1.6 yrs.; height: 168 ± 4.9 cm; weight: 64.4 ± 8.7 kg; body fat%: 28.4 ± 4.5% fat) | 4-day food & activity monitoring. AEE was estimated using MET values | Low AEE estimate: 30.27 ± 12.6 kcal/kg FFM High AEE estimated: 26.1 ± 12.4 kcal/kg FFM |
52% (11/21) were below 30 kcal·kg FFM−1·day−1 while an additional 38% (8/21) were between 30–45 kcal·kg FFM−1·day−1 | N/A |
| Civil 2018 [42] | Vocational ballet students (n = 20; age: 18.1 ± 1.1 years; body mass index: 19.0 ± 1.6 kg·m2; body fat: 22.8 ± 3.4%) | 7 days, including 5 weekdays (with dance training) and 2 weekend days (without scheduled dance training) | Weekdays 38 ± 13 Weekend days 44 ± 13 (p = 0.110). |
Reduced energy availability (30–45 kcal·kg FFM·day−1: 44% LEA (i.e., <30 kcal·kg FFM−1·day−1): 22% |
Association with menstrual dysfunction. |
| Torres-McGehee 2021 [20] |
Collegiate athletes and performing artists (n = 121; age: 19.8 6 ± 2.0 yrs.; height: 168.9 ± 7.7 cm, body mass: 63.6 ± 9.3 kg); equestrian (n = 28), soccer (n = 20), beach volleyball (n = 18), softball (n = 17), volleyball (n = 12), and ballet (n = 26) |
7 consecutive days | All: 19.5 ± 16.1 Equestrian: 21.9 ± 9.9 Volleyball: 18.6 ± 10.9 Softball: 7.8 ± 6.4 Beach Volleyball: 12.44 ± 9.6 |
All: 81% (96/121) Equestrian: 82.1% (23/28) Volleyball: 83.3% (10/12) Softball: 100% (17/17) Beach Volleyball: 94.4% (17/18) Ballet: 96.2% (25/26) Soccer: 30% (6/20) |
N/A |
LEA = Low energy availability defined as: LEA = EA <30 kcal/kg of FFM; Non-conf = Non-conference play; Conf = Conference play; WA = Well adapted; NFOR: Non-functional overreaching; N/A = Not available; AEE = Activity energy expenditure; MET = Metabolic equivalent.