title: Investigating the adaptation of muscle oxygenation to resistance training for elders and young men using near-infrared spectroscopy.
abstract: OBJECTIVE
  The purpose of this study was to investigate the differences in resistance training adaptation on muscle oxygenation between young and elderly subjects. Groups of eleven trained young, untrained young, trained elderly, and untrained elderly (UTE) were recruited.
  
  
  METHODS
  Muscle oxygenation of the vastus lateralis muscle during 20 % maximal voluntary isometric contraction was observed using near-infrared spectroscopy. The oxygen saturation (SpO2) kinetics in the contraction and recovery phases was modeled with a tangential model to extract ΔSpO2 and inflection time (IF). The median frequencies of SpO2 data representing the change of tissue oxygenation oscillation were compared.
  
  
  RESULTS
  The ΔSpO2 values for the trained groups (12.00 ± 7.86%) were significantly higher than those for the untrained groups (5.91 ± 4.36%, P < 0.05), and those for the young groups (11.63 ± 7.52%) were significantly higher than those for the older groups (6.29 ± 4.70%, P < 0.05). In the recovery phase, the IF was significantly longer for the elderly groups (10.32 ± 4.39 s, P < 0.05) than that for the young groups (6.31 ± 3.69 s). The median frequency of tissue oxygenation oscillation was significantly lower for the TE group (0.41 ± 0.12 Hz, P < 0.05) than that for the UTE group (0.57 ± 0.13 Hz).
  
  
  CONCLUSIONS
  The increased ΔSpO2 in trained groups during muscle contraction may be due to lower microvascular O2 pressure. The lower median frequency for the TE group indicates that tissue oxygenation oscillation significantly trended toward low-frequency oscillation, possibly resulting from the enhancement of vascular function.
authors.affiliation: Department of Biomedical Engineering, National Cheng Kung University, No 1. Ta-Hsueh Rd, Tainan, 701, Taiwan.
authors.forename: Tai-You
authors.initials: TY
authors.lastname: Lin
authors.forename: Linda L
authors.initials: LL
authors.lastname: Lin
authors.forename: Ting-Chuan
authors.initials: TC
authors.lastname: Ho
authors.forename: Jia-Jin J
authors.initials: JJ
authors.lastname: Chen
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D052097:Quadriceps Muscle / Q000098:blood supply / Q000378:metabolism / Q000502:physiology*; D055070:Resistance Training; D019265:Spectroscopy, Near-Infrared