Effects of High-Intensity Interval Training and Isoinertial Training on Leg Extensors Muscle Function, Structure, and Intermuscular Adipose Tissue in Older Adults

Abstract

We compared the effects of aerobic high-intensity training (HIT) and isoinertial resistance training (IRT) on the strength, mass, architecture, intermuscular adipose tissue (IMAT) quality, and neuromuscular activation of the quadriceps in elderly subjects. Twelve healthy men (69.3 ± 4.2 years; 77.8 ± 10.4 kg; 1.72 ± 0.05 m) were exposed to 8 weeks of HIT (7 × 2-min cycling repetitions at 90% of trueV.O2peak, 3 times/week) and, after 4 months (detraining), to IRT (4 × 7 maximal concentric–eccentric knee extensions, 3 times/week). Before and after trainings, we measured knee extension isometric (TMVC) and dynamic (TC) maximal concentric torque, anatomical cross-sectional area (ACSA) at 25, 50, and 75% of femur length, quadriceps volume (Vol), IMAT, pennation angle (θp) of the fibers from the vastus lateralis, and voluntary activation (%Act). TMVC and TC were significantly larger only after IRT (P = 0.008); IRT was able to elicit a greater increase of ACSA than HIT; Vol increases similarly and significantly after HIT and IRT (P = 0.003–0.001); IMAT at 50% of femur length decreased after both HIT and IRT (P = 0.001–0.003); physiological cross-sectional area (PCSA) was larger after IRT than before (P = 0.025); specific torque did not change throughout the study (45.5 N cm–2 ± 12.0); %Act of the quadriceps was significantly affected only by IRT (P = 0.011). Both HIT and IRT are able to elicit beneficial modifications of muscular mass, architecture, and quality (reducing IMAT) in elderly subjects in connection with an amelioration of strength. HIT and IRT caused a homogeneous increase of ACSA and of Vol of the quadriceps. PCSA increases, but specific strength per unit of PCSA did not change. The increases of functional torque seemed to be attributed to a parallel increase of %Act and muscle hypertrophy only after IRT. Data suggest that IMAT may be a prominent indicator to track metabolic-dependent activity and skeletal muscle quality.

High Intensity Interval Training Does Not Have Compensatory Effects on Physical Activity Levels in Older Adults

“…Since our results for the physiological and anthropometrical parameters obtained with HIIT have been reported and discussed elsewhere, it is sufficient here to say that they substantiate previous data showing that HIIT can improve cardiovascular performance with substantial positive effects on health-related parameters [8,10,11,[47][48][49].…”

High Intensity Interval Training (HIIT) as a Potential Countermeasure for Phenotypic Characteristics of Sarcopenia: A Scoping Review

“…Of the 32 studies included, 14 were RCTs (Adamson et al, 2014 , 2020 ; Hwang et al, 2016 ; Coetsee and Terblanche, 2017 ; Sculthorpe et al, 2017 ; Aboarrage Junior et al, 2018 ; Malin et al, 2018 ; Martins et al, 2018 ; Ballesta-García et al, 2019 ; Hurst et al, 2019c ; Jiménez-García et al, 2019 ; Nunes et al, 2019 ; Taylor et al, 2019 ; Coswig et al, 2020 ), one was a quasi-experimental, non-randomized, single-blinded controlled study (Losa-Reyna et al, 2019 ), 16 were observational cohort studies (Bruseghini et al, 2015 , 2019 ; Boereboom et al, 2016 ; Guadalupe-Grau et al, 2017 ; Hayes et al, 2017 ; Herbert et al, 2017a , b ; Robinson et al, 2017 ; Wyckelsma et al, 2017 ; Andonian et al, 2018 ; Bartlett et al, 2018 ; Buckinx et al, 2018 , 2019 ; Søgaard et al, 2018 , 2019 ; Snijders et al, 2019 ), and one was a pilot study (although randomized; (Beetham et al, 2019 ) ( Table 1 ). Where a study had multiple outcome measures, they were examined separately.…”

“…In relation to our first objective, which was to search the literature for the effect of HIIT on phenotypic characteristics of sarcopenia in older adults, we observed most studies reported at least one positive change in characteristics when compared to vs. pre-HIIT, vs. non-exercise control, or vs. MICT. In this context, 19 of 20 studies reported an improvement to ≥1 muscle function outcome for ≥1 comparisons examined (vs. pre-HIIT, vs. non-exercise control, or vs. MICT) (Bruseghini et al, 2019 ). Similarly, twelve of 22 reported an improvement to ≥1 muscle quantity outcome for ≥1 comparison examined, and 11 of 12 reported an improvement to for ≥1 physical performance outcome for ≥1 comparison examined.…”

The “Journal of Functional Morphology and Kinesiology” Journal Club Series: Utility and Advantages of the Eccentric Training through the Isoinertial System

“…As eccentric muscle strength declines with age to a lesser degree than other types of muscle strength, it may represent an effective stimulus for adaptation in older adults, playing a key role in successful ageing [ 49 , 50 , 51 ]. In particular, isoinertial resistance exercise has been suggested as a potential training modality in certain aging populations ready for higher resistance exercise stress [ 52 , 53 ], with studies mainly focusing on knee extension [ 53 , 54 , 55 ] and squat [ 56 , 57 ] exercises.…”

“…Flywheel knee extension trainings (8–12 weeks; 3 times/week; 7–12 repetitions; 1–4 sets per session) elicited beneficial modifications in muscle mass, strength, and architecture, and improved the quality of life and functional performances in 68-year old men [ 53 , 55 ] and the peak knee extension power in 70-year old men and women [ 54 ]. Isoinertial squat trainings (6–8 weeks; 2–3 times/week; 9–15 repetitions; 2–4 sets per session) improved mobility, balance, mean concentric propulsive velocity, and power in 65-year old men and women [ 57 ], as well as physical and functional abilities in 68-year old women [ 56 ].…”