title: Cardiorespiratory and hemodynamic responses during repetitive incremental lifting and lowering in healthy males and females.
abstract: The purposes of this study were twofold. First, to evaluate the cardiorespiratory and muscle oxygenation (OXY)/blood volume (BV) responses during repetitive incremental lifting and lowering (RILL) in healthy males and females. Second, to develop a predictive equation for predicting peak aerobic power (VO(2peak)) during RILL from the cardiorespiratory, OXY/BV and body composition variables. Fourteen males and 18 females [mean (SD) for age, height and body mass were: 29.6 (8.2) years; 1.75 (0.07) m; 78.9 (10.4) kg and 23.9 (2.1) years; 1.63 (0.06) m; 62.3 (6.3) kg, respectively] completed a RILL from floor to table height at 10 lifts/min to voluntary fatigue. Cardiorespiratory responses were measured using open circuit spirometry and hemodynamic trends were monitored bilaterally at the third lumbar vertebra via near infrared spectroscopy. Significant sex differences ( p<0.05) were observed for the peak values of oxygen uptake (VO(2peak)), ventilation rate (V(E)), oxygen pulse, BV-max and BV-delta. Erector spinae OXY decreased systematically until VO(2peak )was attained, while BV decreased until approximately 50% of VO(2peak) and then leveled off. Stepwise regression analysis indicated that approximately 75% of the variance in VO(2peak )was predicted from cardiorespiratory, hemodynamic and body composition variables, with the most important predictors for absolute and relative VO(2peak )being V(E) ( r=0.75) and fat mass ( r=-0.63) respectively. Inclusion of left side OXY/BV responses increased the predictability of the common variance in VO(2peak )from 40% to 74%, implying that muscle hemodynamics play an important role in determining VO(2peak )during RILL.
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, T6J-2H9, Edmonton, Alberta, Canada.
authors.forename: Robert T
authors.initials: RT
authors.lastname: Kell
authors.forename: Yagesh
authors.initials: Y
authors.lastname: Bhambhani
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000293:Adolescent; D000328:Adult; D001415:Back / Q000502:physiology; D001810:Blood Volume / Q000502:physiology*; D001823:Body Composition / Q000502:physiology*; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006321:Heart / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D018056:Hemorheology / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000502:physiology*; D016272:Occupational Health; D010101:Oxygen Consumption / Q000502:physiology*; D010507:Periodicity; D012044:Regression Analysis; D012119:Respiration; D015656:Respiratory Mechanics / Q000502:physiology; D012737:Sex Factors; D016474:Weight-Bearing / Q000502:physiology*