Saddle Height Research Articles

EFFECTS OF SADDLE HEIGHT ON JOINT POWER DISTRIBUTION

Previous investigators have reported that saddle height alters metabolic efficiency during sub-maximal cycling. We hypothesized that changes in metabolic efficiency result from alterations in the proportion of total power produced at the ankle, knee, and hip. PURPOSE To determine if altered saddle height elicits changes in the proportion of crank power produced at the ankle, knee, and hip. METHODS Four well-trained male cyclists cycled with their accustomed saddle height and with that height reduced by 6 cm. Subjects maintained a pedaling rate of 100 rpm and a workload of 300 watts for 1 minute. Pedal forces, and pedal and crank position were sampled at 200 Hz. Two-dimensional leg kinematics were computed using the geometric relationships of the 5-bar linkage, and the hip was assumed to remain fixed. Net joint moments were determined using inverse dynamic techniques. Joint powers were calculated as the product of net joint moments and joint angular velocities and were averaged over 7 complete crank revolutions. The proportions of total crank power produced at each joint were determined. The absolute value of relative changes at the hip and knee were also determined. RESULTS Mean relative joint powers at the ankle, knee, and hip did not differ when cycling with the accustomed saddle height (14.4 ± 3.5, 42.4 ± 7.2, and 43.2 ± 5.9% respectively mean±SE) compared with the reduced saddle height (13.2 ± 2.5, 39.0 ± 5.1, and 47.8 ± 3.4%). The absolute values of the changes at the ankle knee and hip were 1.3 ± 0.6, 6.3 ± 2.0, 6.1 ± 2.7% respectively, and the difference at the knee was significantly different than zero (P < .05). CONCLUSION Cycling with a reduced saddle height did not elicit significant changes in joint power distribution. However, the absolute value of shifts in power distribution at the knee joint was found to be significant. Based on these data we conclude that alterations in saddle height do not elicit consistent shifts in power production from one joint to another but do elicit individual shifts.

The Effect of Lower Saddle Height on the Knee Joint during Pedaling Exercise.

The purpose of this study is to investigate the influence of lower saddle height on the knee joint. Five healthy male pedal at 60 rpm against the work load of 100 and 200 W. Three saddle heights of 80, 90 and 100% of trochanteric leg height are selected in this study. During each trial, the position data of the right lower limb's joints by the video camera and the force data of the right pedal by the force sensor are measured. Using these data, the inverse dynamics analysis is done, and the following results are obtained. The peak link force acting on the knee joint and the peak knee extension moment do not indicate any change over the three saddle heights, however, the angles at their peak values shift to the knee flexion as the lower saddle height. These results indicate that the lower saddle would overload at the knee joint.

Effect of annular shape on leaflet curvature in reducing mitral leaflet stress.

Leaflet curvature is known to reduce mechanical stress. There are 2 major components that contribute to this curvature. Leaflet billowing introduces the most obvious form of leaflet curvature. The saddle shape of the mitral annulus imparts a more subtle form of leaflet curvature. This study explores the relative contributions of leaflet billowing and annular shape on leaflet curvature and stress distribution. Both numerical simulation and experimental data were used. The simulation consisted of an array of numerically generated mitral annular phantoms encompassing flat to markedly saddle-shaped annular heights. Highest peak leaflet stresses occurred for the flat annulus. As saddle height increased, peak stresses decreased. The minimum peak leaflet stress occurred at an annular height to commissural width ratio of 15% to 25%. The second phase involved data acquisition for the annulus from 3 humans by 3D echocardiography, 3 sheep by sonomicrometry array localization, 2 sheep by 3D echocardiography, and 2 baboons by 3D echocardiography. All 3 species imaged had annuli of a similar shape, with an annular height to commissural width ratio of 10% to 15%. The saddle shape of the mitral annulus confers a mechanical advantage to the leaflets by adding curvature. This may be valuable when leaflet curvature becomes reduced due to diminished leaflet billowing caused by annular dilatation. The fact that the saddle shape is conserved across mammalian species provides indirect evidence of the advantages it confers. This analysis of mitral annular contour may prove applicable in developing the next generation of mitral annular prostheses.

The Support of Horizontal Vessels Containing High-Temperature Fluids—A Design Study

This paper investigates the behavior of horizontal cylindrical vessels, subjected to thermal loading by high-temperature fluid, where the saddles are fixed to the supporting structure. In order to determine an optimum saddle design, three widely used saddle configurations, with differing saddle heights and top saddle plate extensions, are explored. Thereafter, one of the saddle designs is selected to illustrate a decoupling procedure, for the radial and axial expansions, whereby design charts are obtained to derive the maximum stress values for a range of vessel geometries. The finite element approach, using linear elastic, small displacement analysis, is used throughout.

Exercise tricycle for paraplegics.

The work describes a tricycle that can be used by paraplegics without assistance. Paraplegics can get on and off the tricycle independently, using hydraulic adjustment of the saddle height. The two rear wheels can be swivelled with adjustable hydraulic damping, which avoids the stability problems of a standard tricycle when riding around bends. The principal driving power is assumed to be provided by functional electrical stimulation of the femoral muscles. A hub motor is integrated in the front wheel to increase the radius of action, as additional drive for cycling up gradients and in case muscle force is not sufficient. The desired drive power is adjusted by a throttle grip on the handlebar. The percentage of motor power can also be adjusted. The force applied to the pedal, the absolute angular position of the crank, and the angular velocity of the front wheel are continuously measured by a force measurement pedal and a goniometer. Based on this information, the motor and the functional electrical stimulation of the legs are controlled.

Proper Fit of the Bicycle

After cyclists have carefully made adjustments for proper fit, minor aches and pains may develop before the body adjusts to the new riding posture. This is normal--so resist the temptation to fiddle with the position much. They will become accustomed to the new riding position after a few rides, and cycling performance will be improved. Then they can concentrate on bike handling skills and fitness confident that their riding position is as good as can be. Proper bicycle fit requires careful review of bicycle selection, saddle height for proper leg extension, fore-and-aft positioning of the knee over the pedal, saddle tilt, handlebar position, and positioning of the upper body for optimum comfort and performance. Further research on the effects of maintaining an aerodynamic position for extended periods of time needs to be investigated to review fatigue patterns in lower and upper body musculature. The underlying principle of positioning a cyclist on a bicycle is to remember that the bicycle is adjustable, and the cyclist is adaptable.

Efficiency of pedal forces during ergometer cycling.

The aim of this study was to record the forces applied to the pedal during ergometer cycling and to calculate the effectiveness of these force vectors. Six healthy subjects rode a weight-braked bicycle ergometer at different work loads, pedaling rates, saddle heights, and pedal foot positions. The left lower limb and crank motions were recorded by a cinefilm camera and pedal reaction forces by a Kistler force measuring transducer mounted on the left pedal. The force effectiveness was computed as a ratio between the force tangential to instantaneous direction of pedal movement and the resultant force. The mean force efficiency ratio significantly increased by an increase of the ergometer work load or use of the anterior foot position instead of the posterior. It was not significantly changed due to alterations of the pedaling rate or saddle height.

Joint Motions of the Lower Limb During Ergometer Cycling

The purpose of the study was to study the utilization of range of motion at the hip, knee, and ankle joints during exercise on a bicycle ergometer. Six healthy subjects biked at different workloads, pedaling rates, saddle heights, and pedal foot positions. The subjects were filmed in the sagittal plane with a cine-film camera at 60 frames/sec. The mean hip range of motion (ROM) during normal cycling was 38 degrees ranging from 32-70 degrees hip flexion. The mean knee ROM was 66 degrees ranging from 46-112 degrees knee flexion, and the ankle ROM was 24 degrees ranging from 2 degrees plantarflexion to 22 degrees dorsiflexion. The hip, knee, and ankle joint motions were influenced by changes of the saddle height or pedal foot position. Different workloads had a small but statistically significant influence on the joint motions while different pedaling rates did not significantly change the lower limb joint motions. The range of motion utilized during cycling is approximately equal to, but more flexed compared to level walking and stair walking. The most effective way of increasing the ROM and obtaining more extension of the lower limb joints is to change the saddle height.J Orthop Sports Phys Ther 1988;9(8):273-278.

Load moments about the hip and knee joints during ergometer cycling : Ericson MO, Bratt A. Nisell R, Németh G. Ekholm J. Scand J Rehabil Med 1986; 18: 165–172

The aim of the study was to calculate the magnitudes of moments of force acting about the bilateral hip and knee joint axes during ergometer cycling. Six healthy subjects pedalled a weight-braked bicycle ergometer at different workloads, pedalling rates, saddle heights and pedal foot position. During cycling at 120 Watts, 60 revolutions per minute with mid-saddle height and anterior pedal foot position, the mean peak flexing and extending hip load moments were 34.3 and 8.9 Nm, respectively. Mean peak flexing knee load moments was 28.8 Nm and extending moment was 11.9 Nm. Hip load moments were significantly increased by increasing the ergometer workload or pedalling rate. For knee load moments, workload was the most important factor. The flexing knee load moment did not change with changes in pedalling rate. Different saddle heights or pedal food positions had a slight but not always statistically significant influence on the hip and knee joint loads. The maximum hip and knee joint load moments induced during cycling were small compared with those obtained during other exercises or normal activities such as level walking, stair climbing, and lifting.

Load moments about the hip and knee joints during ergometer cycling

The aim of the study was to calculate the magnitudes of moments of force acting about the bilateral hip and knee joint axes during ergometer cycling. Six healthy subjects pedalled a weight-braked bicycle ergometer at different workloads, pedalling rates, saddle heights and pedal foot position. During cycling at 120 Watts, 60 revolutions per minute with mid-saddle height and anterior pedal foot position, the mean peak flexing and extending hip load moments were 34. 3 and 8. 9 Nm, respectively. Mean peak flexing knee load moments was 28. 8 Nm and extending moment was 11. 9 Nm. Hip load moments were significantly increased by increasing the ergometer workload or pedalling rate. For knee load moments, workload was the most important factor. The flexing knee load moment did not change with changes in pedalling rate. Different saddle heights or pedal food positions had a slight but not always statistically significant influence on the hip and knee joint loads. The maximum hip and knee joint load moments induced during cycling were small compared with those obtained during other exercises or normal activities such as level walking, stair climbing, and lifting.

Tibiofemoral joint forces during ergometer cycling

Six healthy subjects pedaled on a weight-braked bicycle ergometer at different workloads, pedaling rates, saddle heights, and pedal foot positions. The subjects were filmed with a cine-film camera and pedal reaction forces were recorded from a force transducer mounted on the left pedal. Net knee moments were calculated using a dynamic model, and the tibiofemoral shear and compressive force magnitudes were calculated using a biomechanical model of the knee. During cycling at 120 W, 60 rpm, midsaddle height, and anterior pedal foot position, the mean peak tibiofemoral compressive force was 812 N [1.2 times body weight (BW)]. The maximum anteriorly directed tibiofemoral shear force was found to be low (37 N). The compressive and shear forces were significantly increased by an increased ergometer workload. The pedaling rate had no influence on the tibiofemoral force magnitudes. The stress on the ACL was low and could be further decreased by use of the anterior foot position instead of the posterior.

自転車エルゴメータのサドルの高さの決定基準とパワー差の検討

The purpose of this study was to find the effect of bicycle seat height variation on maximum power and to propose how to determine saddle height. Our proposal adjustments of the ergometer to suit the performer was the range of motion(ROM) at knee joint. The ROM at the knee varied from 30° to 70°: these five seat heights corresponded to 30°, 40°, 50°, 60°, 70°. The efficiency criterion was a power output test which required the subject to perform a preset load of 99 wat/min. Peddaling speed was 100rpm. The saddle heights of maximum power out put was 40° of knee flexion. But there was no significant difference at 30°, 40°, 50°, 60° at 5%. These seat heights' efficiency was equal. The efficiency was worse when seat height was more than 70° of knee joint at a significance level of 5%. We suggested the criterion of deciding saddle height was ROM of knee joint. It was a reasonable method.

The forces of ankle joint structures during ergometer cycling.

The ankle joint moment, joint compressive force, and Achilles tendon force obtained during ergometer cycling were calculated by using a quartz force-measuring transducer mounted on the pedal. Six healthy subjects rode in 11 different ways at different workloads, pedalling rates, saddle heights, and pedal foot positions. The mean maximum dorsiflexing load moment about the ankle joint during standardized ergometer cycling was calculated to 30.9 nm. The mean ankle joint compressive force and mean Achilles tendon force measured 1008 N (1.4 times body weight) and 762 N (1.1 times body weight), respectively. The ankle joint moment was significantly changed by a change of workload or pedal foot position.

Muscular activity during ergometer cycling

The aim of the study was to quantify the activity as recorded by electromyography during ergometer cycling in eleven different muscles of the lower extremity. Eleven healthy subjects rode in twelve different ways at different work-load, pedalling rate, saddle height and pedal foot position. Vastus medialis and lateralis, gastrocnemius medialis and lateralis and the soleus muscle were the most activated muscles. Changes in muscle activity during different calibrations were studied in eight of the eleven muscles. An increase in work-load significantly increased the mean maximum activity in all the eight muscles investigated. An increase of the pedalling rate increased the activity in the gluteus maximus, gluteus medius, vastus medialis, medial hamstring, gastrocnemius medialis and soleus muscles. An increase of the saddle height increased the muscle activity in the gluteus medius, medial hamstring and gastrocnemius medialis muscles. Use of a posterior pedal foot position increased the activity in the gluteus medius and rectus femoris muscles, and decreased the activity in the soleus muscle.

Saddle Height for Bicycles

To the Editor.— The letter entitled Errors in Bicycling Technique by David L. Smith, MD (237:1200, 1977), while pointing out some common errors in the growing sport and pastime of cycling, mentions the essential of correct saddle height. While agreeing with Dr Smith that most American bicyclists ride with their saddles too low, there are many who go to the other extreme. The suggestion that a rider should measure the inside length of the leg from groin to floor is good, but to then use 109% of this measurement is not a good idea at all, especially for any distance cycling. A better method of obtaining a proportionately good saddle height is for the rider to sit on the bicycle while being held upright by a friend, then place the heel of the left or right leg on the pedal surface. At this point, the saddle should be adjusted either

Saddle height for bicycles

Saddle height for bicycles

The effect of saddle height on oxygen consumption during bicycle ergometer work

The effect of saddle height upon oxygen consumption during bicycle ergometer work was measured. Five subjects were tested on a continuous work protocol from 50 watts to 200 watts in 25 watt increments at experimental saddle heights of 100%, 103%, 106%, 109%, and 112% of inside leg length measured from the ischium to the floor. Data were recorded on Vo2, Vco2, VE, and heart rate. It was found that Vo2 progressively increased as saddle height increased; the highest Vo2 occurred at the highest experimental setting of 112%; the most effective saddle positions in the experiment as measured by lowest Vo2 per unit of work were 100% and 103%; and there was no significant difference between the VO2 AT 100% AND 103%. It was concluded that in light of our data and earlier data showing power output to be maximized at 104% (by our measurement method), the saddle height of choice should be approximately 103% to 104% of leg length. A convenient and objective method for setting seat height is presented.

Positive and negative muscular work.

Summary.It was the purpose of the present experiments to determine the ratio cost of positive work: cost of megative work under different conditions of work.The cost of the work was expressed as the oxygen uptake per minute in the steady state of work. The work itself consisted in riding a bicycle on the inclined belt of a motordriven treadmill, uphill for positive work, downhill for negative work. The rate of work was expressed in kg/m per minute and defined as the product of the weight of subject plus bicycle and the vertical distance of lifting or lowering this weight per minute.The oxygen uptake per minute (y) plotted against the rate of work (x) was found to lie on two straight lines for the two kinds of work, and the equations for these two lines could be expressed as y = bposx + apos for positive work and y = hneg + aneg for negative work.Under the same conditions of speed, saddle height and pedal length apos and aneg were found to be identical and are assumed to represent the cost of extra work (balancing, postural efforts etc.) plus the resting metabolism. bpos: bneg should consequently represent the ratio cost of positive work: cost of negative work.The ratio bpos: bneg was found to increase from 3.1 ± 0.7 to 6.1 ±w 0.7 when the distance saddle to crank increased from 60 to 90 cm, and the pedal length and velocity of movement were constant.Variation of the pedal length between 8.5 cm and 25.5 cm with constant velocity of muscular movements and saddle height had no statistically significant effect on the ratio, which under these conditions was found to lie between 7.0 and 9.3.With increasing speed of movements the ratio increased from 5.9 to 125, mainly because bneg decreased and approached zero.The results are discussed under consideration of the length‐tension diagrams and the force‐velocity curve of isolated muscle.It is concluded that besides the effects that could be expected from the form of the length‐tension diagrams and from the force‐velocity curve another factor must be responsible for the very low values of bneg and the high value of bpos: brneg. It is tentatively suggested that this factor is the reversal of the chemical processes in excentric muscle contractions previously found by Abbott, Aubert and Hill (1951).The author wishes to express his sincere thanks to Mr. P. Rosenfalck, M. Sc., and to Dr. Steen Knudsen, both of the Neurophysiological Institute, Copenhagen, for their kind help with the statistics in this work and for many suggestive discussions during its progress. Dr. Steen Knudsen designed the filter used as an integrator of the electromyograms in fig. 5.