Phase Angle Is a Marker of Muscle Quantity and Strength in Overweight/Obese Former Athletes

Abstract

Background: An increasing body of evidence indicates that the phase angle (PhA) can be applied as a marker of nutritional status, disease prognosis, and mortality probability. Still, it is not known whether PhA can be used as an indicator of muscular quantity and strength and maximal aerobic capacity in overweight/obese former highly active individuals, an understudied population. This study aimed to analyze the association between PhA with skeletal muscle mass, maximal isometric strength, and maximal aerobic capacity through VO2max, in overweight/obese and inactive former athletes. Methods: Cross-sectional information of 94 (62 males) former adult athletes (age: 43.1 ± 9.4 years old; body mass index: 31.4 ± 4.8 kg/m2) taking part in a weight-loss clinical trial was analyzed. Total fat and fat-free mass were determined by dual-energy X-ray absorptiometry, while skeletal muscle mass was predicted from appendicular lean soft tissue. Values for upper- and lower-body maximal isometric strength were assessed by handgrip and leg press dynamometry. VO2max was determined by indirect calorimetry through a graded exercise test performed on a treadmill. Results: PhA was associated with skeletal muscle mass (r = 0.564, p < 0.001), upper-body strength (r = 0.556, p < 0.001), lower-body strength (r = 0.422, p < 0.001), and VO2max (r = 0.328, p = 0.013). These relationships remained significant for skeletal muscle mass (β = 2.158, p = 0.001), maximal isometric strength (upper-body: β = 2.846, p = 0.012; low-er-body: β = 24.209, p = 0.041) after adjusting for age, sex, and fat mass but not for VO2max (β = −0.163, p = 0.098). Conclusion: Our findings indicated that former athletes with higher values of PhA exhibited greater muscle mass and strength, despite sex, age, and body composition, which suggests that this simple raw BI parameter can be utilized as an indicator of muscle quantity and functionality in overweight/obese former athletes.

Reference Percentiles for Bioelectrical Phase Angle in Athletes

“…The results of this study showed that regardless of sports modality, male athletes have a higher phase angle than their female counterparts. These results are in congruence with previous investigations conducted in the general population and in former athletes [ 15 , 19 ]. The biological mechanism for this observation may be due to the positive correlation of phase angle with muscle mass and the intra-to-extracellular water ratio [ 12 , 29 ], two parameters generally higher in male subjects [ 30 ].…”

“…In the context of sports, changes in phase angle are associated with physical adaptations obtainable after training or nutritional interventions [ 8 ]. Furthermore, recent findings have highlighted the phase angle’s positive association with sport-specific muscle strength and power test outcomes [ 15 , 16 , 17 ].…”

Relationship of Fat Mass Index and Fat Free Mass Index With Body Mass Index and Association With Function, Cognition and Sarcopenia in Pre-Frail Older Adults

“…Increasingly, phase angle is being considered as an indicator of nutritional status, muscle quality, muscle size and function, cellular integrity, and predictor of mortality (63)(64)(65)(66)(67). Phase angle was significantly higher in the lowest FMI and FM/FFM tertile and highest FFMI tertile.…”

Association between Phase Angle from Bioelectric Impedance and Muscular Strength and Power in Physically Active Adults

“…BI is considered a safe method to evaluate PhA, monitor body composition and water compartments. Moreover, it is a portable, non-invasive and inexpensive method, considering each evaluation [ 6 ]. Previous studies have shown that PhA is associated with functionality [ 7 ], muscle mass quantity [ 6 , 8 , 9 ] and muscle quality [ 10 ], as well as with physical performance in different populations and age groups [ 11 ].…”

“…Moreover, it is a portable, non-invasive and inexpensive method, considering each evaluation [ 6 ]. Previous studies have shown that PhA is associated with functionality [ 7 ], muscle mass quantity [ 6 , 8 , 9 ] and muscle quality [ 10 ], as well as with physical performance in different populations and age groups [ 11 ]. More specifically, associations between PhA and knee isokinetic muscle strength and jump performance in adolescent athletes [ 12 ], strength of upper and lower limbs in former athletes [ 6 ], muscle power of upper limbs [ 13 ] and lower limbs in athletes [ 11 ], maximum anaerobic power and fatigue index [ 14 ] and sprint speed [ 15 ] in soccer athletes, were observed.…”