Startup circuit training program reduces metabolic risk in Latino adolescents

Abstract

Purpose: This study aimed to test the effects of a circuit training (CT; aerobic + strength training) program, with and without motivational interviewing (MI) behavioral therapy, on reducing adiposity and type 2 diabetes risk factors in Latina teenagers.

Methods: Thirty-eight Latina adolescents (15.8 ± 1.1 yr) who are overweight/obese were randomly assigned to control (C; n = 12), CT (n = 14), or CT + MI (n = 12). The CT classes were held twice a week (60-90 min) for 16 wk. The CT + MI group also received individual or group MI sessions every other week. The following were measured before and after intervention: strength by one-repetition maximum; cardiorespiratory fitness (V·O 2max) by submaximal treadmill test; physical activity by accelerometry; dietary intake by records; height, weight, waist circumference; total body composition by dual-energy x-ray absorptiometry; visceral adipose tissue, subcutaneous adipose tissue, and hepatic fat fraction by magnetic resonance imaging; and glucose/insulin indices by fasting blood draw. Across-intervention group effects were tested using repeated-measures ANOVA with post hoc pairwise comparisons.

Results: CT and CT + MI participants, compared with controls, significantly increased fitness (+16% and +15% vs -6%, P = 0.03) and leg press (+40% vs +20%, P = 0.007). Compared with controls, CT participants also decreased waist circumference (-3% vs +3%; P < 0.001), subcutaneous adipose tissue (-10% vs 8%, P = 0.04), visceral adipose tissue (-10% vs +6%, P = 0.05), fasting insulin (-24% vs +6%, P = 0.03), and insulin resistance (-21% vs -4%, P = 0.05).

Conclusions: CT may be an effective starter program to reduce fat depots and improve insulin resistance in Latino youth who are overweight/obese, whereas the additional MI therapy showed no additive effect on these health outcomes.

Conflict of interest statement

None of the authors had any financial or personal conflicts of interest.

Figures

FIGURE 1

A–C, Change in V̇O2max, leg press, and bench press values between each intervention groups. Data are presented as mean ± SD. Changes in fitness and strength levels were calculated with repeated-measures ANOVA. There was an overall effect for V̇O2max (P = 0.04), leg press (P = 0.007), and bench press (P = 0.02). a,bMeans not sharing a common superscript letter are significantly different at P ≤ 0.05 based on Bonferroni multiple comparisons.

FIGURE 2

A–C, Change in adiposity measures (i.e., waist circumference, SAT and VAT) between intervention groups. Data are presented as mean ± SD. Changes in adiposity measures were calculated with repeated-measures ANOVA. There was an overall effect for waist (P < 0.001), SAT (P = 0.04), and VAT (P = 0.05). a,bMeans not sharing a common superscript letter are significantly different at P ≤ 0.05 based on Bonferroni multiple comparisons.

FIGURE 3

A and B, Change in fasting insulin and HOMA-IR between intervention groups. Data are presented as mean ± SD. Change in fasting insulin and HOMA-IR was calculated with repeated-measures ANOVA. There was a significant overall effect for fasting insulin (P = 0.03) and for HOMA-IR (P = 0.05). a,bMeans not sharing a common superscript letter are significantly different at P ≤ 0.05 based on Bonferroni multiple comparisons.