title: Prediction of Cardiorespiratory Fitness by the Six-Minute Step Test and Its Association with Muscle Strength and Power in Sedentary Obese and Lean Young Women: A Cross-Sectional Study.
abstract: Impaired cardiorespiratory fitness (CRF) is a hallmark characteristic in obese and lean sedentary young women. Peak oxygen consumption (VO2peak) prediction from the six-minute step test (6MST) has not been established for sedentary females. It is recognized that lower-limb muscle strength and power play a key role during functional activities. The aim of this study was to investigate cardiorespiratory responses during the 6MST and CPX and to develop a predictive equation to estimate VO2peak in both lean and obese subjects. Additionally we aim to investigate how muscle function impacts functional performance. Lean (LN = 13) and obese (OB = 18) women, aged 20-45, underwent a CPX, two 6MSTs, and isokinetic and isometric knee extensor strength and power evaluations. Regression analysis assessed the ability to predict VO2peak from the 6MST, age and body mass index (BMI). CPX and 6MST main outcomes were compared between LN and OB and correlated with strength and power variables. CRF, functional capacity, and muscle strength and power were lower in the OB compared to LN (<0.05). During the 6MST, LN and OB reached ~90% of predicted maximal heart rate and ~80% of the VO2peak obtained during CPX. BMI, age and number of step cycles (NSC) explained 83% of the total variance in VO2peak. Moderate to strong correlations between VO2peak at CPX and VO2peak at 6MST (r = 0.86), VO2peak at CPX and NSC (r = 0.80), as well as between VO2peak, NSC and muscle strength and power variables were found (p<0.05). These findings indicate the 6MST, BMI and age accurately predict VO2peak in both lean and obese young sedentary women. Muscle strength and power were related to measures of aerobic and functional performance.
authors.affiliation: Cardiopulmonary Physiotherapy Laboratory, Physiotherapy Department, Federal University of Sao Carlos, Sao Carlos, Sao Paulo, Brazil.
authors.forename: Lívia Pinheiro
authors.initials: LP
authors.lastname: Carvalho
authors.affiliation: Cardiopulmonary Physiotherapy Laboratory, Physiotherapy Department, Federal University of Sao Carlos, Sao Carlos, Sao Paulo, Brazil.
authors.forename: Luciana
authors.initials: L
authors.lastname: Di Thommazo-Luporini
authors.affiliation: Kinanthropology Department, University of Quebec in Montreal, Montreal, Quebec, Canada.
authors.forename: Mylène
authors.initials: M
authors.lastname: Aubertin-Leheudre
authors.affiliation: Medicine Department, Federal University of Sao Carlos, Sao Carlos, Sao Paulo, Brazil.
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Bonjorno Junior
authors.affiliation: Medicine Department, Federal University of Sao Carlos, Sao Carlos, Sao Paulo, Brazil.
authors.forename: Cláudio Ricardo
authors.initials: CR
authors.lastname: de Oliveira
authors.affiliation: Santa Casa de Misericórdia de Sao Carlos, São Carlos, SP, Brazil.
authors.forename: Rafael Luís
authors.initials: RL
authors.lastname: Luporini
authors.affiliation: Cardiopulmonary Physiotherapy Laboratory, Physiotherapy Department, Federal University of Sao Carlos, Sao Carlos, Sao Paulo, Brazil.
authors.forename: Renata Gonçalves
authors.initials: RG
authors.lastname: Mendes
authors.affiliation: Cardiopulmonary Physiotherapy Laboratory, Physiotherapy Department, Federal University of Sao Carlos, Sao Carlos, Sao Paulo, Brazil.
authors.forename: Katiany Thais Lopes
authors.initials: KT
authors.lastname: Zangrando
authors.affiliation: Cardiopulmonary Physiotherapy Laboratory, Physiotherapy Department, Federal University of Sao Carlos, Sao Carlos, Sao Paulo, Brazil.
authors.forename: Renata
authors.initials: R
authors.lastname: Trimer
authors.affiliation: Integrative Physiology Laboratory, Physical Therapy Department, College of Applied Health Sciences, University of Illinois Chicago, Chicago, Illinois, United States of America.
authors.forename: Ross
authors.initials: R
authors.lastname: Arena
authors.affiliation: Cardiopulmonary Physiotherapy Laboratory, Physiotherapy Department, Federal University of Sao Carlos, Sao Carlos, Sao Paulo, Brazil.
authors.forename: Audrey
authors.initials: A
authors.lastname: Borghi-Silva
mesh_terms: D000328:Adult; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D009765:Obesity / Q000503:physiopathology*; D010101:Oxygen Consumption; D010809:Physical Fitness / Q000502:physiology*; D011237:Predictive Value of Tests; D057185:Sedentary Behavior; D013851:Thinness / Q000503:physiopathology; D055815:Young Adult