title: The age related slow and fast contributions to the overall changes in tibialis anterior contractile features disclosed by maximal single twitch scan.
abstract: This work aimed to verify if maximal electrically evoked single twitch (STmax) scan discloses the relative functional weight of fast and slow small bundles of fibres (SBF) in determining the contractile features of tibialis anterior (TA) with ageing. SBFs were recruited by TA main motor point stimulation through 60 increasing levels of stimulation (LS): 20 stimuli at 2Hz for each LS. The lowest and highest LS provided the least ST and STmax, respectively. The scanned STmax was decomposed into individual SBF STs. They were identified when twitches from adjacent LS were significantly different and then subtracted from each other. Nine young (Y) and eleven old (O) subjects were investigated. Contraction time (CT) and STarea/STpeak (A/PT) were calculated per each SBF ST. 143 and 155 SBF STs were obtained in Y and O, respectively. Y: CT and A/PT range: 45-105ms and 67-183mNs/mN, respectively. Literature data set TA fast fibres at 34% so, from the arrays of CT and A/PT, 65ms and 100mNs/mN were identified as the upper limit for SBF fast ST classification. O: no SBF ST could be classified as fast.
  
  
  
  STmax scan reveals age-related changes in the relative contribution of fast and slow SBFs to the overall muscle mechanics.
authors.affiliation: Department of Clinical and Experimental Sciences, University of Brescia, Viale Europa 11; 25123 Brescia, Italy. Electronic address: claudio.orizio@unibs.it.
authors.forename: Claudio
authors.initials: C
authors.lastname: Orizio
authors.affiliation: Department of Clinical and Experimental Sciences, University of Brescia, Viale Europa 11; 25123 Brescia, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Cogliati
authors.affiliation: Rehabilitation Service, Fondazione Teresa Camplani-Casa di Cura Domus Salutis, Via Lazzaretto, 3, 25123 Brescia, Italy.
authors.forename: Luciano
authors.initials: L
authors.lastname: Bissolotti
authors.affiliation: Department of Clinical and Experimental Sciences, University of Brescia, Viale Europa 11; 25123 Brescia, Italy.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Diemont
authors.affiliation: Department of Clinical and Experimental Sciences, University of Brescia, Viale Europa 11; 25123 Brescia, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Gobbo
authors.affiliation: Department of Neurobiology, University School of Physical Education, 27/39 Królowej Jadwigi St., 61-871 Poznan, Poland.
authors.forename: Jan
authors.initials: J
authors.lastname: Celichowski
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D000818:Animals; D004558:Electric Stimulation; D005260:Female; D005528:Foot; D006801:Humans; D007866:Leg; D009119:Muscle Contraction / Q000502:physiology*; D018656:Muscle Fibers, Fast-Twitch / Q000502:physiology*; D018657:Muscle Fibers, Slow-Twitch / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000502:physiology*; D055815:Young Adult
keywords: Ageing; Neuromuscular electrical stimulation; Single twitch; Single twitch modelling; Skeletal muscle