Strength Training and Insulin Resistance: The Mediating Role of Body Composition

Table 4

Mean differences in HOMA-IR in men across categories of strength training based on simple, hourly cut-points, after adjusting for potential confounders.

Outcome variable	Minutes of strength training
	None		Low		Moderate		High
	Mean	SE	Mean	SE	Mean	SE	Mean	SE
HOMA-IR
Model 1	2.59^a	0.12	2.24^a,b	0.36	1.96^b	0.21	1.94^b	0.20	11.40	<0.0001
Model 2	2.62^a	0.08	2.37^a,b	0.32	2.00^b	0.17	1.94^b	0.12	13.88	<0.0001
Model 3	2.66^a	0.09	2.45^a,b	0.32	2.07^b	0.17	2.10^b	0.11	12.65	<0.0001
Model 4	2.61^a	0.07	2.37^a,b	0.32	2.01^b	0.16	1.95^b	0.10	11.98	<0.0001
Model 5	2.62^a	0.08	2.38^a,b	0.32	2.03^b	0.17	2.00^b	0.12	11.91	<0.0001
Model 6	2.62^a	0.07	2.42^a,b	0.31	2.08^b	0.15	2.09^b	0.10	10.22	<0.0001
Model 7	2.66^a	0.09	2.58^a,b	0.32	2.15^b	0.15	2.23^b	0.09	9.26	<0.0001

^a,bMeans on the same row with the same superscript letter are not significantly different (). SE = standard error of the mean. Means have been adjusted according to the covariates included in the model. Model 1 included age, race, and year of assessment as covariates. Model 2 included age, race, year, pack-years of smoking, other physical activity, and BMI. Model 3 included the same covariates as Model 2 plus waist circumference. Model 4 included the same covariates as Model 2 plus fat-free mass. Model 5 included the same covariates as Model 2 plus body fat percent. Model 6 included the same covariates as Model 2 plus the fat-free mass index. Model 7 included the same covariates as Model 2 plus waist circumference, fat-free mass (kg), body fat percentage, and the fat-free mass index. For the categories representing minutes of strength training, None included men reporting ≤10 minutes per week of strength training. Low included men reporting >10 minutes per week and <60 minutes per week, Moderate included men reporting ≥ to 60 minutes per week and < 120 minutes per week, and High included men reporting ≥120 minutes per week.