This article was in the Vic Masters November 2004 News and Results newsletter (http://home.vicnet.net.au/~vicvets/introfr.html). And forwarded to me by Colin.
RUNNING STRIDE LENGTH AND STRIDE FREQUENCY By Earl Fee
All serious runners should be interested in how stride length and stride frequency changes with increased speed, and how these change with increased age. A better understanding will indicate what may need to be worked on or improved in your particular case. This can lead to improved speed and/or greater running economy.
Stride Length and Frequency for Distance Runners
At the 1984 Olympics Jack Daniels Ph.D. investigated the stride length and frequency of male and female runners for distance events from 800 metres to marathon. “The fastest turnover rates were among the 800 metre specialists, and the next were the 1500 metre runners, but from the 3000 meters on up to the marathon there was little-variation in turnover rate.” “The women took only a few more steps per minute than the larger men who had much longer strides.” For the 3000m and longer distances with nearly constant turnover the slower speeds are accomplished by shorter strides. In these distance events nearly all runners have a turnover rate of near 180 to 190 steps per minute. Also at my local YMCA I checked the steps per minute of five different runners going at different but moderate rate speeds and all were within a step or two of 180 steps per minute. For a given long distance runner the turnover is essentially the same within a few percent whether the pace is racing at five minutes per mile or training at above six minutes per mile. If turnover is low such as about 160 steps per minute for some beginners, it is beneficial to change with practice to 180 steps per minute.
Competitors in the middle distance events have considerably longer strides and the turnover may be up to about 220 steps per minute or 110 strides per minute.
For distance runners to increase speed it is more productive to work on increasing stride length than frequency. Increased frequency will result in greater energy usage compared to increased stride length. My experience running in the deep end of a pool confirms the above. In pool running a longer more powerful arm and leg motion is about six percent faster than a rapid arm and leg action. (Note in pool running as in land running the arms drive the legs.) Or alternately, to achieve the same speed as in the long powerful arm action, with the faster arm action—the fast arm action is more tiring. Similarly, in swimming the stroke length is more important than stroke frequency: a more powerful arm stroke will result in more speed with less energy than an increase in stroke rate.
Stride Length and Frequency for Sprinters
For sprinters, as running speed approaches maximum, frequency changes more than stride length. A maximum stride length is achieved and then further speed is achieved by increase in frequency of turnover. Hence to increase speed, sprinters need to work on both stride length and frequency.
Effect of Ageing on Stride Length and Stride Frequency
Dr. Nancy Hamilton of U of Northern Iowa investigated the effect of ageing on running form by video taping runners at the Masters meet in San Diego and the World Masters Championships in Eugene both in 1989 (Journal of Applied Biomechanics, vo!9, p 15-26, 1993). She compared the biomechanics of fast and slow, and older and younger athletes. From computer analysis she learned of ways to preserve specific aspects of running form to slow down the decline in running speed with age.
Facts
The following are some of Hamilton’s significant findings for runners:
1. “Stride rate dropped off only a small amount, not statistically significant, after age 55.
2. Runners in their 80’s had only 4 to 5% slower stride rates than 35 year olds.
3. Stride length of 35-39 year olds had stride lengths of 4.72 meters compared with 90 year olds of 2.84 metres - a 40% decline. (Note one stride = two steps.) Stride length declined after age 40.” Similarly for walkers: with increasing age, stride rate stays nearly the same but stride length (gait) decreases drastically.
Hamilton’s Conclusions
She concluded the decline in stride length and velocity was due to the following in order of importance:
1. “Range of motion of hips during backward motion of the support leg decreased 38% between the ages of 35 and 90. This was most significant after age 50. [I call this “decline in toeoff angle,” i.e., the angle between the back leg and the ground at push-off. ]
2. Range of motion of knees during swing phase or forward return of leg decreased 33% (from 123 to 95 degrees) between the ages of 35 and 90. This was most significant after age 60. [I call this “decline in knee flexion angle.”] With increased age there was increased time spent in the support phase, or time spent in contact with the ground.”
Recommendations to Reduce Decline in Toe-Off Angle:
• A strong thrust at toe-off also involves powerful calves, quads, hip flexors, gluteus muscles, and ankles. Weight train these areas once or twice per week. Also daily stretching of these areas is essential. One leg squats are recommended to develop mainly the quads, and glutes, but also the hamstrings.
• To strengthen glutes in particular lie on stomach with legs stretched out; raise one straight leg about 0.3 metres at your foot, and lower to floor. Do 3 sets of 10 reps daily.
• Strengthening the hip flexors will result in a higher knee of the return leg before touchdown. This in turn results in a more powerful toe-off thrust and a longer stride.
• Leg swinging exercises will result in more flexible hips. I have always been a big advocate of flexibility of the hips to assist running form and economy.
• The lunge exercise is very useful to increase the toe-off angle. Ensure that the back lower leg is parallel to the ground to achieve a great stretch of the hip flexor muscle. Toe raise exercises will result in a for more powerful toe-off
Recommendations to Reduce Decline in Knee Flexion:
Ideally the knee should be well flexed during forward return so the foot is near the buttocks. This results in a short lever with the center of gravity of the leg close to the pivot point -the hip. Hence the effort to swing the leg forward is much reduced resulting in a fast return of the leg to the front.
• Lighter shoes will assist a faster return since rotating a heavy object at end of a lever particularly a long one (as in a 90 degree bent knee) is harder work.
• Stretch the quad, hip flexor and hamstring muscles daily. The butt kick drill should be done regularly.
Recommendations to Reduce the Contact Time During Support Phase
• The usual recommendation is to dorsiflex the foot (flexed upwards) before it strikes the ground. This also assists to have the foot land under the center of gravity (c. of g.) and helps prevent some possible braking by landing slightly in front of the c. of g.
• The running ABC drills and plyometrics will assist to reduce contact time. Plyometrics, particularly one legged, will build strength and coordination in the foot, ankle, shin, calf, thigh, hip, and will activate the central nervous system as well. With the drills practiced regularly it is possible to save about 0.01 per step. For example, this is a saving of over one minute in a 10K race or one second in a 200-metre race.
• Pilates exercises regularly will improve hip and knee mobility
The following typical fast movements: fast feet drill and fast arms drill, punching bag drill, and fast moving of weights will help preserve the neural pathways and the fast twitch muscles. This will also result in faster reaction times.
Some Further Useful Exercises
The following will assist stride length and stride frequency:
• Running uphill fast will enhance the dorsiflection of the feet and increase knee lift while building leg strength.
• Running downhill fast or running fast with a strong wind at your back will increase turnover. For all runners, strength and flexibility and reaction time are essential, to increase or maintain stride length and stride frequency. But for distance runners a greater oxygen capacity will assist to a greater extent than the above three. This is why elite runners are able to maintain long strides at reasonable frequencies at high speeds-making it look easy. Their superior oxygen uptake allows for the additional energy required for a continuous smooth longer stride. The anaerobic threshold runs, VO2max intervals and long aerobic runs improve the distance runner’s aerobic capacity, which in turn allows for a longer stride.
Earl Fee: Author of “How To Be A Champion from 9 to 90..” Articles from “The Canadian Masters Athletic Association - MASTERPIECE - Summer 2004 No. 130
RUNNING STRIDE LENGTH AND STRIDE FREQUENCY By Earl Fee
All serious runners should be interested in how stride length and stride frequency changes with increased speed, and how these change with increased age. A better understanding will indicate what may need to be worked on or improved in your particular case. This can lead to improved speed and/or greater running economy.
Stride Length and Frequency for Distance Runners
At the 1984 Olympics Jack Daniels Ph.D. investigated the stride length and frequency of male and female runners for distance events from 800 metres to marathon. “The fastest turnover rates were among the 800 metre specialists, and the next were the 1500 metre runners, but from the 3000 meters on up to the marathon there was little-variation in turnover rate.” “The women took only a few more steps per minute than the larger men who had much longer strides.” For the 3000m and longer distances with nearly constant turnover the slower speeds are accomplished by shorter strides. In these distance events nearly all runners have a turnover rate of near 180 to 190 steps per minute. Also at my local YMCA I checked the steps per minute of five different runners going at different but moderate rate speeds and all were within a step or two of 180 steps per minute. For a given long distance runner the turnover is essentially the same within a few percent whether the pace is racing at five minutes per mile or training at above six minutes per mile. If turnover is low such as about 160 steps per minute for some beginners, it is beneficial to change with practice to 180 steps per minute.
Competitors in the middle distance events have considerably longer strides and the turnover may be up to about 220 steps per minute or 110 strides per minute.
For distance runners to increase speed it is more productive to work on increasing stride length than frequency. Increased frequency will result in greater energy usage compared to increased stride length. My experience running in the deep end of a pool confirms the above. In pool running a longer more powerful arm and leg motion is about six percent faster than a rapid arm and leg action. (Note in pool running as in land running the arms drive the legs.) Or alternately, to achieve the same speed as in the long powerful arm action, with the faster arm action—the fast arm action is more tiring. Similarly, in swimming the stroke length is more important than stroke frequency: a more powerful arm stroke will result in more speed with less energy than an increase in stroke rate.
Stride Length and Frequency for Sprinters
For sprinters, as running speed approaches maximum, frequency changes more than stride length. A maximum stride length is achieved and then further speed is achieved by increase in frequency of turnover. Hence to increase speed, sprinters need to work on both stride length and frequency.
Effect of Ageing on Stride Length and Stride Frequency
Dr. Nancy Hamilton of U of Northern Iowa investigated the effect of ageing on running form by video taping runners at the Masters meet in San Diego and the World Masters Championships in Eugene both in 1989 (Journal of Applied Biomechanics, vo!9, p 15-26, 1993). She compared the biomechanics of fast and slow, and older and younger athletes. From computer analysis she learned of ways to preserve specific aspects of running form to slow down the decline in running speed with age.
Facts
The following are some of Hamilton’s significant findings for runners:
1. “Stride rate dropped off only a small amount, not statistically significant, after age 55.
2. Runners in their 80’s had only 4 to 5% slower stride rates than 35 year olds.
3. Stride length of 35-39 year olds had stride lengths of 4.72 meters compared with 90 year olds of 2.84 metres - a 40% decline. (Note one stride = two steps.) Stride length declined after age 40.” Similarly for walkers: with increasing age, stride rate stays nearly the same but stride length (gait) decreases drastically.
Hamilton’s Conclusions
She concluded the decline in stride length and velocity was due to the following in order of importance:
1. “Range of motion of hips during backward motion of the support leg decreased 38% between the ages of 35 and 90. This was most significant after age 50. [I call this “decline in toeoff angle,” i.e., the angle between the back leg and the ground at push-off. ]
2. Range of motion of knees during swing phase or forward return of leg decreased 33% (from 123 to 95 degrees) between the ages of 35 and 90. This was most significant after age 60. [I call this “decline in knee flexion angle.”] With increased age there was increased time spent in the support phase, or time spent in contact with the ground.”
Recommendations to Reduce Decline in Toe-Off Angle:
• A strong thrust at toe-off also involves powerful calves, quads, hip flexors, gluteus muscles, and ankles. Weight train these areas once or twice per week. Also daily stretching of these areas is essential. One leg squats are recommended to develop mainly the quads, and glutes, but also the hamstrings.
• To strengthen glutes in particular lie on stomach with legs stretched out; raise one straight leg about 0.3 metres at your foot, and lower to floor. Do 3 sets of 10 reps daily.
• Strengthening the hip flexors will result in a higher knee of the return leg before touchdown. This in turn results in a more powerful toe-off thrust and a longer stride.
• Leg swinging exercises will result in more flexible hips. I have always been a big advocate of flexibility of the hips to assist running form and economy.
• The lunge exercise is very useful to increase the toe-off angle. Ensure that the back lower leg is parallel to the ground to achieve a great stretch of the hip flexor muscle. Toe raise exercises will result in a for more powerful toe-off
Recommendations to Reduce Decline in Knee Flexion:
Ideally the knee should be well flexed during forward return so the foot is near the buttocks. This results in a short lever with the center of gravity of the leg close to the pivot point -the hip. Hence the effort to swing the leg forward is much reduced resulting in a fast return of the leg to the front.
• Lighter shoes will assist a faster return since rotating a heavy object at end of a lever particularly a long one (as in a 90 degree bent knee) is harder work.
• Stretch the quad, hip flexor and hamstring muscles daily. The butt kick drill should be done regularly.
Recommendations to Reduce the Contact Time During Support Phase
• The usual recommendation is to dorsiflex the foot (flexed upwards) before it strikes the ground. This also assists to have the foot land under the center of gravity (c. of g.) and helps prevent some possible braking by landing slightly in front of the c. of g.
• The running ABC drills and plyometrics will assist to reduce contact time. Plyometrics, particularly one legged, will build strength and coordination in the foot, ankle, shin, calf, thigh, hip, and will activate the central nervous system as well. With the drills practiced regularly it is possible to save about 0.01 per step. For example, this is a saving of over one minute in a 10K race or one second in a 200-metre race.
• Pilates exercises regularly will improve hip and knee mobility
The following typical fast movements: fast feet drill and fast arms drill, punching bag drill, and fast moving of weights will help preserve the neural pathways and the fast twitch muscles. This will also result in faster reaction times.
Some Further Useful Exercises
The following will assist stride length and stride frequency:
• Running uphill fast will enhance the dorsiflection of the feet and increase knee lift while building leg strength.
• Running downhill fast or running fast with a strong wind at your back will increase turnover. For all runners, strength and flexibility and reaction time are essential, to increase or maintain stride length and stride frequency. But for distance runners a greater oxygen capacity will assist to a greater extent than the above three. This is why elite runners are able to maintain long strides at reasonable frequencies at high speeds-making it look easy. Their superior oxygen uptake allows for the additional energy required for a continuous smooth longer stride. The anaerobic threshold runs, VO2max intervals and long aerobic runs improve the distance runner’s aerobic capacity, which in turn allows for a longer stride.
Earl Fee: Author of “How To Be A Champion from 9 to 90..” Articles from “The Canadian Masters Athletic Association - MASTERPIECE - Summer 2004 No. 130
