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Titlow, L., Ishee, J., & Anders, A. (1986, March). Effects of knee angle on submaximal bicycle ergometry. / Les effets de l ' angle du genou lors d ' une epreuve sousmaximale sur bicyclette ergometrique. Journal of Sports Medicine & Physical Fitness, 26(1), 52-54. Retrieved March 13, 2009, from SPORTDiscus database.
Abstract
The purpose of this study was to determine the effects of knee angle on submaximal bicycle ergometry. Sixteen male high school students volunteered to participate in the study. Ages ranged from 16 to 19 years. Resting heart rate and exercise heart rates for three work bouts were determined using carotid palpation. All subjects completed three 6-minute submaximal work bouts at 600 kpm on a Monark bicycle ergometer. Treatment 1 was with a knee ankle between 175-180 degrees, treatment 2 was 155-160 degrees, and treatment 3 was 135-140 degrees. Treatment conditions were randomly assigned to eliminate trend effects and spaced one week apart to reduce training effects. Data were analyzed using a repeated measures ANOVA design. The results indicated that knee angle had no effect on heart rate during submaximal bicycle ergometry. This appears to support other studies of mechanical work during bicycle ergometry. Within the limitations of the study, it was concluded that knee angle has no effects on submaximal bicycle ergometry. Subjects should be allowed to utilize a saddle height and knee angle that feels most comfortable.
Notes
Used 3 knee angles 175-180, 155-160, and 135-140. Not a very good description was provided on how this was measured. A goniometer was used, but there is no other indication when the measurement is taken. The introduction indicates 175 and 180 degree extension is the most comfortable from "practical experience" and this is measured when the "tip of the foot on the peddle at the bottom of the arc." This seems to be a baseless assumption with poor measuring accuracy.
Cadence 50-55 rpm at 100 Watts for 6 minutes.
High school age subjects, not trained cyclists.
No significant difference were found for predicted VO2max and heart rates.
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Nordeen-Snyder, KS. (1977, 1977 Summer). The effect of bicycle seat height variation upon oxygen consumption and lower limb kinematics. Medicine And Science In Sports, 9(2), 113-117. Retrieved July 7, 2009, from MEDLINE database.
Abstract
VO2 was obtained for 10 women bicycling on rollers at 3 saddle heights (SH), 95, 100 and 105% trochanteric height. Kinematic patterns described by the hip, knee, ankle and foot were discerned from one pedal cycle at each of the 3 SH. Subjects cycled on a Fuji Dynamic 10 10-speed bicycle, at 60 rpm, (a work load of 799 kpm/min was applied by a tensioning belt from a bicycle ergometer) until they reached steady state. Expired air was then collected and cine films were taken during gas collection. The 100% SH was most efficient, mean values for 95, 100 and 105% SH were 1.69, 1.61 and 1.74 lit/min, respectively. Kinematic patterns showed no variation in the range of motion (ROM) at the hip, values at the dead centers (DC) did change. The ROM at the knee varied from 69 to 82.9 degrees, 95 to 105% SH, values at the DC varied also. Plantar flexion (PF) at bottom dead center increased by 10% from 95 to 105% SH. Foot angle showed no significant variation with increasing SH. The major adaptations to increases in SH are found at the knee and in ankle PF.
http://0-search.ebscohost.com.eos.eou.edu:80/login.aspx?direct=true&db=c...
Notes
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Mandroukas, K., Angelopoulou, N., Christoulas, K., & Vrabas, I.S. (2000, June). Cardiorespiratory and metabolic responses during straight and bent knee cycling. The Journal Of Sports Medicine And Physical Fitness, 40(2), 145-149. Retrieved March 13, 2009, from MEDLINE database.
Sather has PDF
Abstract
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 degrees), 2) bent knee (140 degrees). 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), V(E) 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.
NOTES
Used a stepwise test to exhaustion.
Cadence was 60 RPM.
Straight leg condition was knee fully extended (180 degrees) and bent leg condition knee was at 140 degrees.
Explanations for increase VO2 include
1. Force length relation of rectus femoris is different in cycling and running, indicating the force-length properties are variable. The different lengths where the thigh muscle was exerting force may have altered the cardiovascular response.
2. Mechanical conditions under which the muscle contracts affects blood flow. Mechanical pumping of blood may not have been enough during the low vs the high seat height due to the smaller range of motion.
3. Different muscle recruitment pattern may have worked the Type II fibers more. These fibers produce more heat, require greater blood flow, and consume more oxygen for the same tension.
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Price, D., & Donne, B. (1997, August). Effect of variation in seat tube angle at different seat heights on submaximal cycling performance in man. / Effet de la variation de l ' angle d ' inclinaison du tube de selle pour differentes hauteurs de la selle, sur la performance sous-maximale de cyclisme chez un homme. Journal of Sports Sciences, 15(4), 395-402. Retrieved July 7, 2009, from SPORTDiscus database.
Abstract
The effect of seat tube angle at selected seat heights (96, 100 and 104 percent trochanteric height) on heart rate, VO2 and lower limb kinematics was evaluated in 14 competitive male road racing cyclists during discontinuous submaximal exercise (200 W) on an air-resistance ergometer at seat tube angles of 68, 74 and 80 degrees. The tests were randomized to complete the nine combinations (three seat heights, three tube angles) in opposite directions from a starting tube angle of 74 degrees and 100 percent trochanteric height to avoid any time or sequence bias. Power efficiency was calculated for each combination from work done and VO2. All results were analysed using ANOVA for repeated measures. At a seat tube angle of 80 degrees, mean VO2 was significantly lower and power efficiency significantly higher compared with an angle of 74 degrees at all three seat heights, while heart rate was significantly lower only at a seat height equal to trochanteric height. At a seat tube angle of 74 degrees, mean VO2 and heart rate were significantly lower and power efficiency significantly higher compared with an angle of 68 degrees at all three seat heights. Hip range of movement and maximum and minimum hip angle were significantly less at an angle of 80 degrees compared with 68 degrees. Further biomechanical analysis suggested that the improvement in cycling efficiency observed at steeper seat tube angles was produced in part by the resultant altered ankling pattern of the cyclist.
Notes
Saddle was slid fore and aft to make the seat tube and "effective" angle. No mention of the saddle type or where on the saddle each sat.
At seat heights of 104% of trochanteric height (recorded knee angle 22.5 degrees, SD 6.5), VO2 and heart rate were significantly higher and power efficiency significantly lower than both 96 (recorded knee angle 33.6 degrees, SD 6.0) and 100% (recorded knee angle 43.1 degrees, SD 7.1) trochanteric height.
No mention of controlling for torso angle.
As seat height increased, ankle plantarflexion increased at the bottom of the pedal stroke, while at the top of the pedal stroke minimum angle did not change.
Suggested possible explanations for improved cardiorespiratory efficiency with increased seat tube ankle include the effect of the hip angle on the cardiovascular system, muscle force-length relationship, and alterations of ankling.
Speculated that increasing tube angle improves effective force transfer during the second half of the pedal stroke (90 to 180).
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Peveler, W. W. (2008, July). Effects of saddle height on economy in cycling. Journal Of Strength And Conditioning Research / National Strength & Conditioning Association, 22(4), 1355-1359. Retrieved March 13, 2009, from MEDLINE database.
Abstract
Research has demonstrated that properly adjusting saddle height is important for both performance and injury prevention during cycling. Peer-reviewed literature recommends the use of a 25 degrees to 35 degrees knee angle for injury prevention and 109% of inseam for optimal performance. Previous research has established that these 2 methods do not produce similar saddle heights. Previous research has also compared anaerobic power among a 25 degrees knee angle, a 35 degrees knee angle, and 109% of inseam and found an increase in anaerobic power at a 25 degrees knee angle. While anaerobic power production has been compared between these 2 methods, aerobic power and economy have not been. The purpose of this study was to determine the difference in economy between these 2 methods of adjusting saddle height. Fifteen subjects, consisting of 5 cyclists (all men) and 10 noncyclists (2 men and 8 women), participated in this study. A graded exercise protocol was utilized in order to determine intensity for the remaining trials. On the last 3 trials, subjects rode for 15 minutes at the resistance at which they reached 70% of Vo2max on a cycle ergometer. Vo2, heart rate (HR), and rating of perceived exertion (RPE) were compared to detect differences in economy between saddle heights. No significant differences were noted in HR or RPE. Vo2 was found to be significantly lower at a saddle height set with a 25 degrees knee angle when compared to a 35 degrees knee angle and 109% of inseam. Findings from this study support the use of a 25 degrees knee angle for both performance and injury prevention.
NOTES
Since Peveler's previous study examined anaerobic power, this study was an attempt to examine the effect of saddle height on aerobic values.
Cyclists used their own pedals and shoes and non cyclists used cage platform pedals. Cyclists kept cadence at 90 rpm and noncyclists 50 rpm.
Used a static goniometer reading for the knee angle. No mention of a control for torso angle.
When examining knee angles of the cyclists in the study, it was 26.8 which could indicate a specificity of training effect. However, the researchers point out the non cyclists demonstrated the same effect.
The 109% method landed 74% of the subjects outside the 25 to 35 range, with 45% of these at less than 25 and 55 at greater than 35.
Referenced 3 studies that showed a specificity of training effect.
Heil, Derrick, & Whitlesey The relationship between preferred and optimal positioning during submaximal cycle ergometry (1997)
Peveler, Bishop, Smith, & Richardson (2004) training in an aero position
Peveler, Bishop, Smith, & Richardson (2005) training in an aero position
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