EFFECT OF HIGH INTENSITY TRAINING AND ISOINERTIAL TRAINING ON INTERMUSCULAR ADIPOSE TISSUE IN OLDER ADULTS

Introduction Recent findings suggest that, in elderly, Intermuscular Adipose Tissue (IMAT) may be associated with inactivity and that exercise training may be able to mitigate the content of IMAT (Murphy et al., 2012; Santanasto et al., 2011). The purpose was to determine how IMAT can be influenced by exercise and if a greater reduction in IMAT occurs with concurrent aerobic High Intensity Training (HIT) and Isoinertial Resistance Training (IRT). Methods 12 moderately active older adults (age: 69.4±4.3 yy; weight: 78.5±10.5 kg; height: 171.2±5.3 cm; BMI: 22.9±2.7 kg/m2; V'O2max: 29.5±4.1 mL/kg/min) were exposed to 8 weeks of: i) HIT training with 7 two-minute cycling repetitions at 90% of V'O2max, 3 times/week and, after 4 months, ii) IRT performed with an isoinertial leg press (YoYo Technology AB) comprised 4×7 maximal concentric-eccentric knee extensions, 3 times/week. MRI of the mid-thigh was examined to determine changes in muscle composition (Cross Sectional Area (CSA) and IMAT) after exercise intervention using SliceOmatic image analysis software (Rossi et al., 2010). IMAT was defined as adipose tissue area visible between quadriceps muscle groups. Results Quadriceps CSA increased significantly after HIT and after IRT by 6% (P<0.05) and 7% (P<0.05) respectively. IMAT decreased after HIT and IRT by 31% (P<0.05) and 41% (P<0.05) respectively. Net thigh lean mass increased significantly after both training by 10% (P<0.05). Discussion Our data, in contrast with Jacobs (2014) and Goodpaster (2008) but in agreement with other previous studies (Murphy et al., 2012; Santanasto et al., 2011), show that IMAT decrease after a 8 weeks exercise intervention in older adults both after HIT and IRT. Preliminary data show that exercise training performed at high intensity in older adults may contrast skeletal muscle fat infiltration. Our study is non-randomized, not-counterbalanced and limited by small sample size: additional studies are needed to determine the most effective exercise (type, intensity, modalities) able to decrease IMAT and how this decrease may positively affect health in elderly.