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THE JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS
A Journal on Applied Physiology, Biomechanics, Preventive Medicine,
Sports Medicine and Traumatology, Sports Psychology
Indexed/Abstracted in: Chemical Abstracts, CINAHL, Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 1,111
The Journal of Sports Medicine and Physical Fitness 2000 June;40(2):145-9
Cardiorespiratory and metabolic responses during straight and bent knee cycling
Mandroukas K., Angelopoulou N., Christoulas K., Vrabas I. S.
From the Ergophysiology Laboratory Department of Physical Education and Sports Sciences Aristotelian University o f Thessaloniki, Greece
Background. This study examined the influence of knee angle on the cardiorespiratory system loading during submaximal and maximal stationary cycle ergometry.
Methods. Experimental design and participants: eighteen untrained women (age: 21±1.88 years, weight: 57±5.75 kg, height: 165±5.03 cm, values are mean±SD) volunteered as subjects and underwent two-cycle ergometer incremental (Jaeger ER900) tests: 1) straight knee (180°), 2) bent knee (140°). Measures: oxygen uptake (VO2), ventilation (VE) and respiratory exchange ratio (RER) were measured continuously during each test using an open circuit spirometry and blood lactate concentration was determined by means of an enzymatic method.
Results. Comparing cycling with “straight knee” to cycling with “bent knee” at 50 W, heart rate (HR), VE and VO2 were significantly higher (10.6%, 12.5%, 17.8%). At 100 W, blood lactate was significantly lower (10.8%) while VO2 and RER was higher (5.5%, 7.1%). During maximal exercise, the total exercise time was significantly longer (11.2%) and VE, VO2 and HR were significantly higher during cycling with “straight knee” compared to cycling with “bent knee”. No significant difference in peak lactate was evident between the two sitting positions.
Conclusions. The results of this study indicate that cycling with bent knee requires lower oxygen uptake while pedaling with straight knee is the only way to reach VO2max during cycle testing, since the cardiorespiratory system is fully taxed.