TABLE 1.
Summary of studies that has investigated fat-free mass quantitative changes and glucose homeostasis in response to either resistance or mixed training intervention or a comparison.
| Study | Intervention (Modality) | Sample | FFM and FM changes | Glucose homeostasis | Association |
| Miller et al., 1984 | 10-week, 3/week (10 exercises, 3 sets of 8 REPS) | 10 Young male college students | ↑ FFM ↔ FM | ↓ OGTT insulin AUC | Positive association: ↑ FFM and ↓ OGTT insulin No association: ↑ FFM and ↓ OGTT glucose |
| Miller et al., 1994 | 16-weeks, 3/week (14 exercises, 3 to 15 REPS) | 11 Healthy older (58 ± 1 years) men (BMI = 26.9 ± 1.0) | ↑ FFM ↓ FM | ↔ F-Glucose and Glucose OGTT ↓ F-insulin and insulin AUC ↑ Glucose disposal during clamp | No association shown. |
| Bucci et al., 2016 | 4-months, three times/week | Older frail women offspring of normal weight/lean mothers (n = 20) and or overweight/obese mothers (n = 17) Avg age: 72.3 and 71.5 years; Avg BMI: 26.6 and 27.9. | ↔ Overall BC ↑ Quadriceps mass and adductor longus mass. | ↔ F-Glucose and F-insulin ↑Muscle GU ↑ Whole-body IS (OOM group only) | Positive association: ↑ GU per kg and ↑ FFM |
| Roberts et al., 2013 | 12 weeks, 3/week (Progressive overload – from 2 sets of 12–15 to 3 sets of 6–8 REPS) | 28 Healthy young (avg 21.5 years) men, overweight/obese (avg BMI 30.9) | RT group: ↑ FFM ↓ Total FM ↓ Trunk FM | RT group: ↔ HbA1c ↑ GT (OGTT) | No association shown. |
| Shaibi et al., 2006 | 16-week, 2/week (Multiple sets, moderate intensity/high volume, multiple joint exercises) | 11 overweight (Avg BMI 32.5) adolescent males (Avg 15.1 years) | RT group: ↑ FFM ↓ %BF Control group: ↑ FFM | RT group: ↑ IS (FSIGVTT) Control group: ↔ | IS changes independent of BC changes. |
| Dionne et al., 2004 | 6 months, 3/week (9 exercises targeting major muscle groups, 3 sets of 10 REPS) | 33 Young (27.8 ± 3.5 years) and 12 old (66.6 ± 4.9) women (avg BMI: young; 21.9 ± 2.3; old: 25.4 ± 2.6) | Young: ↑ FFM Old: ↑ FFM ↓ FM | Young: ↑ M (+38mg/min) Old: ↔ M | No significant improvement in young when reported relative to FFM. |
| Lee et al., 2012 | 3 months, 3/week AT (40–60 min, 50–70% VO2peak) or RT (10 whole-body exercises, 1–2 sets 8–12 REPS, 60% 1RM) | 42 Obese adolescents (avg age: control = 14.8, AT = 15.2, RT = 14.6) | AT group: ↓ FM RT group: ↑ FFM ↓ FM Control group: ↔ | AT group: ↔ GT (OGTT) ↔ IS RT group: ↔ GT (OGTT) ↔ ↑ IS Control group: ↔ | No association shown. |
| Kogure et al., 2016 | 16 weeks, 3/week (Strength and hypertrophy focused) | 45 Young (28 ± 5.4 years) [women with (n = 47) or without (n = 52)] PCOS | With PCOS: ↑ FFM Without PCOS: ↔ | With PCOS: ↑ HOMA-IR Without PCOS: ↔ | Positive association: FFM and HOMA-IR in PCOS and control at baseline and post-intervention. Changes in FFM (LM/height2) were independent of changes in HOMA-IR after the intervention. |
| Poehlman et al., 2000 | 6-months, 3 days/week AT (endurance-based) or RT (target intensity: 80% 1RM) | 51 Premenopausal (age range 18–35 years; BMI < 26) | AT group: ↔ FFM and thigh CSA ↑ Muscle attenuation RT group: ↑ FFM and thigh CSA ↑ Muscle attenuation | AT group: ↑ M RT group: ↑ M | When IS was expressed relative to FFM (mg/kg FFM/min), it improved significantly only in the AT group. |
| Glouzon et al., 2015 | 6-month, 3/week (Mixed intervention) | 48 Post-menopausal (avg age 60 ± 5.0 years) women | ↑ FFM ↑ FFMI ↑ Appendicular FFM | ↑ F-glucose ↔ F-insulin ↔ HOMA-IR | Baseline: Positive: ↑ FFMI and HOMA-IR Positive: ↑ appendicular FFMI and HOMA-IR Post-intervention: Positive: ΔFFMI and ΔHOMA-IR |
| Amankwaah et al., 2019 | 9-month, mixed intervention (RT 2 days/week, RT 1 day/week) | Middle-aged men (n = 69) and women (n = 83) with mild obesity (avg BMI 30.0 ± 2.7 kg/m2) | ↑FFM ↓ FM | ↑ F-glucose ↔ HOMA-IR | Increases in FFM did not predict changes in measured cardiometabolic health outcomes. Although the relation between IS and Δ FFM was significant when expressed relative to body weight, it was not when expressed absolutely or relative to baseline FFM. |
| Fukushima et al., 2016 | 6 months, 3 days/week (Mixed intervention) | 92 Obese (BMI: 33.2 ± 4.6) women (avg age 40.9 ± 10.4 years) | ↓ FFMI ↓ FM | ↓ HOMA-IR ↓ F-glucose ↓ F-insulin | ΔHOMA-IR was inversely associated with Δ%FFM (relative to weight). |
| Cuff et al., 2003 | 16 weeks, RT or mixed intervention (AT: aerobic classes; RT: 5 exercises, 2 sets of 12 REPS) | 28 postmenopausal women with T2D (avg age: control: 60 ± 2.9; AT+RT: 63.4 ± 2.2; AT: 59.4 ± 1.9) | Both groups: ↑ FFM (SM CSA) ↓ Low-density SM | AT: ↔ GIR Mixed: ↑ GIR | Positive association: ↑ SM CSA and ↑ GIR. |
AT, aerobic training; Avg, average; AUC, area under the curve; BMI, body mass index (kg/m2); BC, body composition; CSA, cross-sectional area; F-glucose, fasting glucose; F-insulin, fasting insulin; FFM, fat-free mass; FFMI, fat-free mass index (kg/m2); FM, fat mass; GIR, glucose infusion rate; GT, glucose tolerance; GU, glucose uptake; HOMA-IR, homeostatic model assessment for insulin resistance; M, hyperinsulinemic-euglycemic clamp-derived insulin sensitivity; IS, insulin sensitivity; OGTT, oral glucose tolerance test; REPS, repetitions; RM, maximal repetition; RT, resistance training; SM, skeletal muscle; T2D, type 2 diabetes.