How to Calculate Optimal Stride Length and Stride Frequency Using Trochanter Length

By Curtis Taylor, University of Oregon

I became a track coach because I didn’t want to do math. Now that I am a track coach, I spend a lot of time doing math. – Curtis Taylor

Definitions

Table 1: Performance Metrics, Symbols, and Units
Performance Metric	Symbol	Units	Comments
Distance	D	m	Measured in meters.
Time	T	s	Measured in seconds.
Velocity	V	m/s	Distance divided by Time (D/T).
Stride Frequency	SF	Hz	Number of foot contacts per second measured in Hertz.
Stride Length	SL	m	Distance between consecutive foot contacts measured in meters.

Relationship of Sprint Performance Metrics

A sprinters velocity is determined by stride length and stride frequency. A sprinter can increase velocity by increasing their stride length, increasing their stride frequency, or both. The relationship among these three performance metrics can be expressed by the equation:

Equation 1: V = SL * SF

This equation can be rewritten as:

Equation 2: SL = V / SF

and

Equation 3: SF = V / SL

The table below shows the relationship of these three performance metrics for a range of values.

Table 2: Stride Frequency, Velocity, and Stride Length
	5.30	5.20	5.10	5.00	4.90	4.80	4.70	4.60	4.50	4.40	4.30	4.20	4.10	4.00	3.90
12.50	2.36	2.40	2.45	2.50	2.55	2.60	2.66	2.72	2.78	2.84	2.91	2.98	3.05	3.13	3.21
12.00	2.26	2.31	2.35	2.40	2.45	2.50	2.55	2.61	2.67	2.73	2.79	2.86	2.93	3.00	3.08
11.75	2.22	2.26	2.30	2.35	2.40	2.45	2.50	2.55	2.61	2.67	2.73	2.80	2.87	2.94	3.01
11.50	2.17	2.21	2.25	2.30	2.35	2.40	2.45	2.50	2.56	2.61	2.67	2.74	2.80	2.88	2.95
11.25	2.12	2.16	2.21	2.25	2.30	2.34	2.39	2.45	2.50	2.56	2.62	2.68	2.74	2.81	2.88
11.00	2.08	2.12	2.16	2.20	2.24	2.29	2.34	2.39	2.44	2.50	2.56	2.62	2.68	2.75	2.82
10.75	2.03	2.07	2.11	2.15	2.19	2.24	2.29	2.34	2.39	2.44	2.50	2.56	2.62	2.69	2.76
10.50	1.98	2.02	2.06	2.10	2.14	2.19	2.23	2.28	2.33	2.39	2.44	2.50	2.56	2.63	2.69
10.25	1.93	1.97	2.01	2.05	2.09	2.14	2.18	2.23	2.28	2.33	2.38	2.44	2.50	2.56	2.63
10.00	1.89	1.92	1.96	2.00	2.04	2.08	2.13	2.17	2.22	2.27	2.33	2.38	2.44	2.50	2.56
9.75	1.84	1.88	1.91	1.95	1.99	2.03	2.07	2.12	2.17	2.22	2.27	2.32	2.38	2.44	2.50
9.50	1.79	1.83	1.86	1.90	1.94	1.98	2.02	2.07	2.11	2.16	2.21	2.26	2.32	2.38	2.44
9.25	1.75	1.78	1.81	1.85	1.89	1.93	1.97	2.01	2.06	2.10	2.15	2.20	2.26	2.31	2.37
9.00	1.70	1.73	1.76	1.80	1.84	1.88	1.91	1.96	2.00	2.05	2.09	2.14	2.20	2.25	2.31
8.75	1.65	1.68	1.72	1.75	1.79	1.82	1.86	1.90	1.94	1.99	2.03	2.08	2.13	2.19	2.24
8.50	1.60	1.63	1.67	1.70	1.73	1.77	1.81	1.85	1.89	1.93	1.98	2.02	2.07	2.13	2.18
8.25	1.56	1.59	1.62	1.65	1.68	1.72	1.76	1.79	1.83	1.88	1.92	1.96	2.01	2.06	2.12
8.00	1.51	1.54	1.57	1.60	1.63	1.67	1.70	1.74	1.78	1.82	1.86	1.90	1.95	2.00	2.05
7.75	1.46	1.49	1.52	1.55	1.58	1.61	1.65	1.68	1.72	1.76	1.80	1.85	1.89	1.94	1.99
7.50	1.42	1.44	1.47	1.50	1.53	1.56	1.60	1.63	1.67	1.70	1.74	1.79	1.83	1.88	1.92

Table 2 above shows the relationship among three sprint performance metrics: velocity, stride frequency, and stride length.
Stride Frequency – The top row is stride frequency measured in foot contacts per second. The table includes stride frequencies from 3.90 to 5.30 foot contacts per second.
Velocity – The left column is velocity measured in meters per second. The table includes velocities from 7.50 to 12.50 m/s.
Stride Length – All other numbers in the table are stride length, measured in meters, for the corresponding velocity and stride frequency.
The region in pink is an unnaturally high stride frequency.
The region in yellow is an unnaturally low stride frequency.
Example – An athlete with a stride frequency of 4.70 foot contacts per second and a velocity of 10.00 m/s will have a stride length of 2.13 meters.

How to Measure Trochanter Length

Figure 1: The Trochanter Length is measured from the floor in bare feet to the top of the greater trochanter.

Steps to measure the trochanter length are the following:

Athlete stands erect on the floor in bare feet.
Palpate the hip by firmly pushing the tissue to locate the top of the greater trochanter.
Measure from the floor to the top of the greater trochaner in centimeters.
Measure both sides and average the two measurements.
Record the length for each athlete.