Sunday, December 7, 2014

Youth Distance Running Limits

We've all heard stories of wonderkids that run amazing distances or times at a very young age, but we also have seen our share of injury and burnout stories from pushing kids too far, too fast, too young.  An overuse injury on a growing body, especially prior to finishing puberty, can create a lifelong problem.

I have spent many years as a runner, as a coach and as a dad of a youth runner.  I have no specific training nor am I in the medical field.  That being said, I think I've used my experience and my mathematical abilities to come up with a workable formula for reasonable limits on the distance that youth runners should complete.

First, the formulas (explanations will follow):

Maximum Daily/Event Distance (km):
        (Age in years ^ 2) / 10
Maximum Weekly Distance (km):
        Max Day amount * Age in years ^ 0.5 (sq root of age) * Season Factor
 Season Factor:
        Off-season: 50%    Normal Peak: 75%   Post-Puberty/Elite: 100%

The Maximum Daily Event Distance came from observations of many youth runners from a Summer track program I coached during high school and college, as well as the participation success from races that I helped organize with my running club.  I came up with general rules of 7 years old for a 5k and 10 years old for a 10k, in high school before running a half-marathon and around 21 for a marathon.  I noticed that this essentially fit a mathematical equation and used the extrapolated results at other ages. 

From that straightforward calculation, I began to review guidelines for weekly mileage limits.  From experience, I wanted to limit the number of days of running for younger ages and eventually settled on the square root of the age as the multiplier.  That is not to suggest that a 16 year old can only run 4 days a week, though that would be the case if they are running longer distances each day (equal to their max daily distance * season factor).  In practice, their daily distance will be lower, allowing them to run 5-6 days comfortably.

The results allow for the dedicated and enthusiastic young runner to compete at a challenging level, but protects them from over-zealous coaches and parents and the resulting over-use injuries.

The charts below show the results at each age and then flips the calculation to show the age needed for a particular distance.

AGE
Single Run (km)
Single Run (miles)
4
1.6
                0.99
5
2.5
                1.55
6
3.6
                2.24
7
4.9
                3.05
8
6.4
                3.98
9
8.1
                5.03
10
10
                6.22
11
12.1
                7.52
12
14.4
                8.95
13
16.9
              10.50
14
19.6
              12.18
15
22.5
              13.98
16
25.6
              15.91
17
28.9
              17.96
18
32.4
              20.14
19
36.1
              22.44
20
40
              24.86
21
44.1
              27.41



Normal/Peak
Post-Puberty/Elite
AGE
Weekly (km)
Weekly (miles)
Weekly (km)
Weekly (miles)
4
           2.40
           1.49
           3.20
           1.99
5
           4.19
           2.61
           5.59
           3.47
6
           6.61
           4.11
           8.82
           5.48
7
           9.72
           6.04
         12.96
           8.06
8
         13.58
           8.44
         18.10
         11.25
9
         18.23
         11.33
         24.30
         15.10
10
         23.72
         14.74
         31.62
         19.65
11
         30.10
         18.71
         40.13
         24.94
12
         37.41
         23.25
         49.88
         31.00
13
         45.70
         28.40
         60.93
         37.87
14
         55.00
         34.18
         73.34
         45.58
15
         65.36
         40.62
         87.14
         54.16
16
         76.80
         47.73
       102.40
         63.64
17
         89.37
         55.54
       119.16
         74.06
18
       103.10
         64.07
       137.46
         85.43
19
       118.02
         73.35
       157.36
         97.80
20
       134.16
         83.38
       178.89
       111.18
21
       151.57
         94.20
       202.09
       125.60

Off season/Pre-season weekly totals would be half the Elite amount
















































Age
Age
Distance
(years)
(yr mo)
1 mile
     4.01
4yr
2 miles
     5.67
5yr 8mo
5k
     7.07
7yr 1mo
8k
     8.94
8yr 11mo
10k
   10.00
10yr
10 miles
   12.68
12yr 8mo
Half-marathon
   14.52
14yr 6mo
20 miles
   17.94
17yr 11mo
Marathon
   20.54
20yr 6mo





What do you think?

2 comments:

Unknown said...

Well done. I like it.

Unknown said...

This is great! Well done! I have always said lets start with a short distance (5k, 10k) and work up from there. A 3-5 year plan depending on age and experience.