Ericson, M. (1986). On the biomechanics of cycling. A study of joint and muscle load during exercise on the bicycle ergometer. Scandinavian Journal Of Rehabilitation Medicine. Supplement, 16, 1-43.
The aim of the study was to quantify the load induced in the lower limb joints and muscles during exercise on a bicycle ergometer and to study how these loads changed with adjustments of the bicycle ergometer or cycling technique. The forces, load moments and muscular power output acting on and about the hip, knee and ankle joints during cycling were determined using cine-film, pedal force measurements and biomechanical calculations based upon static and dynamic mechanics. The muscular activity of eleven lower limb muscles was recorded and quantified using EMG. The load moments acting about the bilateral hip, knee and ankle joint axes were found to be generally lower than those induced during normal level walking. The varus and valgus load moments acting about the antero-posterior knee joint axis were approximately the same as those induced during walking. The tibio-femoral compressive joint force and the anteriorly directed tibio-femoral shear force mainly stressing the anterior cruciate ligament were low. The talocrural joint compressive force and achilles tendon tensile force were low compared to those in level walking. The magnitude of lower limb muscular activity during cycling approximated that obtained during walking, with three major exceptions. M. vastus medialis et lateralis were more activated during cycling than during walking, and tibialis anterior was less activated. The hip extensor muscles produced 27%, hip flexors 4%, knee extensors 39%, knee flexors 10% and ankle plantar flexors 20% of the total positive mechanical work. Of the four parameters studied (workload, pedalling rate, saddle height, pedal foot position) workload was the most important adjustment factor for change of joint load and muscular activity. An increased pedalling rate increased the muscular activity in most of the muscles investigated, generally without changing the joint load. Increased saddle height decreased the maximum flexing knee load moment, but did not significantly change the flexing hip or dorsiflexing ankle load moment. Muscular activity in most of the muscles investigated was not generally changed by different saddle heights. Use of a posterior foot position instead of an anterior decreased the dorsiflexing ankle load moment, increased the gluteus medius and rectus femoris activity, and decreased soleus muscular activity but did not significantly change the hip or knee moments. It is suggested that cycling might be a useful exercise in the rehabilitation of patients with injuries to the anterior cruciate ligament, medial collateral ligament of the knee or achilles tendon.
Mid saddle height approximately 113 percent of distance between ischial tuberosity and medial malleolus.
120 watts, 60 rpm, mid saddle height, and anterior pedal foot position.
This study provides an excellent summary of previous force pedal studies.
Subjects were students with "ordinary daily and recreational" cycling experience.
Picture of subject shows wires dangling down from pedals. Flat bar stationary bicycle with torso angle fairly upright.
Conditions studied. 120 watts and 240 watts. Pedalling rates 40, 60, 80, 100 rpm. Saddle heights 102, 113, 120 % of iscial tuberosity and medial malleolus. Mid saddle height corresponded to 109% of symphysis pubis height recommended by Hamley and Thomas (1967) and Nordeen-Snyder (1977). Problem: "The saddle heights were adjusted to the nearest fixed saddle position with a maximum error of +/- 1.5 cm" (p. 20). Handlebars were kept level with the saddle. Trunk was inclined forwards 20-30 degrees from vertical. Posterior foot position was 10 cm backward (instep) from the anterior (metatarsus II or ball of foot) position.
Saddle height measured from greatest distance of saddle surface to center of upper pedal surface.
The vastus medialis, vastus lateralis and soleus muscles were the most active. Tibialis anterior is less active then during walking.
Of all the parameters (work-load, pedaling rate, saddle height, pedal foot position) workload was the most important adjustment that led to change.
An increased saddle height caused an increase in activity of the gluteus medius, medial hamstring, and gastrocnemius muscles. The other muscles studied were not significantly changed due to saddle height.
Ericson. M. O., Nisell, R., Arborelius, U. P., & Ekholm, J. (1985). Muscular activity during ergometer cycling. Scandinavian Journal Of Rehabilitation Medicine, 17(2), 53-61.
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.
This is a replication of information reported as study 1 in Ericson (1986).
Jorge, M., Hull, M.L. (1986). Analysis of EMG measurements during bicycle pedalling. Journal Of Biomechanics, 19(9), 683-694.
Activity of eight leg muscles has been monitored for six test subjects while pedalling a bicycle on rollers in the laboratory. Each electromyogram (EMG) data channel was digitized at a sampling rate of 2 kHz by a minicomputer. Data analysis entailed generating plots of both EMG activity regions and integrated EMG (IEMG). For each test subject, data were recorded for five cases of pedalling conditions. The different pedalling conditions were defined to explore a variety of research hypotheses. This exploration has led to the following conclusions: Muscular activity levels of the quadriceps are influenced by the type of shoes worn and activity levels increase with soft sole shoes as opposed to cycling shoes with cleats and toeclips. EMG activity patterns are not strongly related to pedalling conditions (i.e. load, seat height and shoe type). The level of muscle activity, however, is significantly affected by pedalling conditions. Muscular activity bears a complex relationship with seat height and quadriceps activity level decreases with greater seat height. Agonist (i.e. hamstrings) and antagonist (i.e. quadriceps) muscles of the hip/knee are active simultaneously during leg extension. Regions of peak activity levels, however, do not overlap. The lack of significant cocontraction of agonist/antagonist muscles enables muscle forces during pedalling action to be computed by solving a series of equilibrium problems over different regions of the crank cycle. Regions are defined and a solution procedure is outlined.
This study has a saddle height at the recommended position and a low position only. These are 100% of trochanter height and 95% respectively.
Point out shortcoming of previous research: discrepancies in foot-to-pedal connections, different equipment used, and variability of test subjects.
Fig 2 on page 685 has some interesting comparisons between previous studies shown in the form of circular diagrams the depict the muscle activity during the pedal stroke.
Report Hamley and Thomas (1967) conclude (based on oxygen consumption) the most efficient seat height is 109% of symphysis pubis height. Nordeen-Snyder (1977) states 100% of trochanter height is more efficient. Both yield similar results.
The authors conclude, based on the reports, that muscle activity levels bear an inverse relationship to saddle height.
Subjects used the same size bicycle as they normally used and rode on rollers to simulate actual riding since no lateral support is provided and both wheels spinning gives a more natural feel. Used 90 PSI. This is low for tires nowadays. Subjects were tourist, recreational rider, 2 former racers, and 2 racers.
Anthropometric data recorded: height, weight, trochanter length, experience. Trochanter length is distance from greater trochanter to the floor with subject standing straight-legged on bare feed.
A problem with studies like Jorge & Hull study and the others Hamley and Thomas (1967) and Nordeen-Snyder (1977) is that saddle height is measured from the surface of the pedal platform to the top of the saddle. The variety of pedal and cleat styles coupled with difference saddle designs available today can created significant differences in the functional knee angle if this is the saddle height measurement technique.
Study had 5 cases. One in 52 x 19 gear. Another the same with soft sole shoes. Third, a low power 52 x 23 gear. Fourth a 52 x 15 gear. Fifth, was a 52 x 19 in the low seat height position. All at 80 rpm.
Large increases in muscle activity were seen for the single joint muscles which act to extend the knee.
All hip extensors muscles including the hamstring exhibited greater activity in a high power condition compared to low.
Gluteus Maximus showed no change in the lower saddle position.
Muscle activity was confirmed with greater resistance. However some anomalies included a lack of increase in gastroc activity at higher pedal loads. Hamstrings and tibialis anterior activity increased with decreased pedal load. Also, a lack of marked decrease took place in the quadriceps at lower pedal loads. Researchers indicate it may be possible that subjects changed their pedaling technique based on load. Also, there was variability between subjects.
This study confirmed the oxygen consumption studies showing less efficiency at lower seat heights. An increase in oxygen consumption is the result of increased muscle activity.
HOUTZ, S.J., & FISCHER F.J. (1959, January). An analysis of muscle action and joint excursion during exercise on a stationary bicycle. The Journal Of Bone And Joint Surgery. American Volume, 41-A(1), 123-131.
Subjects 3 healthy young adult women. Experienced bicycle riders.
Lowest seat position was 21 inches from center of "pedal sprocket" and other position was 4 inches higher.
Purpose of study was for examining rehabilitation.
Conclusion: Height of saddle does not influence timing of the muscle activity but the exercise is performed with less effort with a higher saddle.
Subjects were very upright on their stationary bicycle and wearing dress shoes. Bike had beach-cruiser bars on it. Perceptions of the "ease" of pedaling at the higher seat height were subjective observations by the researcher and subject.