0000000000040004
AUTHOR
Niina Sippola
Neuromuscular function during drop jumps in young and elderly males
The Hoffman reflex (H-reflex), indicating alpha-motoneuron pool activity, has been shown to be task - and in resting conditions - age dependent. How aging affects H-reflex activity during explosive movements is not clear at present. The purpose of this study was to examine the effects of aging on H-reflexes during drop jumps, and its possible role in drop jump performance. Ten young (26.8 ± 2.7 years) and twenty elderly (64.2 ± 2.7 years) subjects participated in the study. Maximal drop jump performance and soleus H-reflex response (H/M jump) 20 ms after ground contact were measured in a sledge ergometer. Maximal H-reflex, maximal M-wave, Hmax/Mmax-ratio and H-reflex excitability curves wer…
Plyometrisen ja konsentrisen nopeusvoimaharjoittelun vaikutukset lihasjännekompleksin toimintaan ja rakenteeseen
Voimaharjoittelulla on mahdollista saada muutoksia hermolihasjärjestelmän toimintaan ja rakenteeseen. Toistaiseksi on olemassa vähän tutkittua tietoa plyometrisen nopeusvoimaharjoittelun vaikutuksista lihasjännekompleksin toimintaan ja rakenteeseen. Tutkimuksen tarkoituksena oli määrittää plyometrisen ja konsentrisen nopeusvoimaharjoittelun vaikutuksia lihasjännekompleksin toimintaan ja rakenteeseen 12 viikon harjoittelun aikana. Tutkimukseen osallistui 12 20-30 –vuotiasta tervettä miestä, jotka jaettiin kahteen ryhmään (konsentrinen; CON ja plyometrinen; SSC). CON ryhmä suoritti harjoittelun paineilmalaitteilla ja SSC ryhmä hyppyharjoitteluna kelkkaergometrissä. Molemmat ryhmät harjoitteli…
Effects of a Heart Rate–Based Recovery Period on Hormonal, Neuromuscular, and Aerobic Performance Responses During 7 Weeks of Strength Training in Men
The purpose of this study was to compare hormonal, neuromuscular, and aerobic performance changes between a constant 2-minute interset recovery time and an interset recovery time based on individual heart rate (HR) responses during a 7-week (3 sessions per week, 3 × 10 repetition maximum [RM]) hypertrophic strength training period. The HR-dependent recovery time was determined with a Polar FT80 HR monitor, whereas the control groups used constant 2-minute periods between sets. From 24 male subjects who were divided in 2 equal groups, 21 completed the study (FT80, n = 12; CONTROL, n = 9). Serum blood samples analyzed for testosterone (TES) and cortisol (COR) were taken before and after the 7…
Age dependency of neuromuscular function and dynamic balance control
Abstract The purpose of the present study was to examine whether static and dynamic balance control are related to neuromuscular function and ageing. For this purpose, we constructed a new dynamic balance measurement system that simulates natural falling. Ten young (age 21–31 years) and 20 elderly (age 60–70 years) men participated in the experiment. Maximal isometric torque (MVC) and activation level were measured from the quadriceps and plantar flexor muscles. The H-reflex, V-wave, and maximal M-wave were measured from the soleus muscle. In dynamic balance control, anterior-posterior centre-of-pressure swaying was 74±8.1 mm in the young men and 91.5±19.4 mm in the elderly men (P<0.05), wh…