There’s a tried and true pre-race secret for runners to achieve optimum results. Not adding extra miles. And not a shocking nutrition hack.

To really build your body to last when it counts, you need to run less. Yes, you heard right, it’s time to cut back.

This is not what performance oriented runners want to hear. But a significant reduction in training before an event (more commonly known as tapering) is scientifically proven to be an effective strategy.

How Tapering Works

If the idea of tapering makes you feel antsy, consider the facts: evidence proves that runners who lower their mileage just before a race reduce lactic acid build-up and muscle fatigue.[1] The extra rest you give your body allows it to store additional glycogen for energy during competition.

How Long Should You Taper?

A 2007 analysis on tapering found runners who reduced training by 60% two weeks before a race saw up to a 6% improvement in performance. For example, say you completed your last 5K in 21 minutes. If you were to taper before your next race, you could potentially cut your time to 19:74.

Finding the right balance is a little tricky. If you taper for too long you can lose conditioning. But too little tapering can leave you tired and unprepared on the day of the race.

According to studies published in the International Journal of Sports Medicine, the optimal taper length is from seven days to three weeks.[2] The specifics depend on the distance of your upcoming race. The studies found the ideal lengths for popular races were:

• Marathon: 19 to 22 days
• 15k to 30k: 11 to 14 days
• 10k to 5k: 7 to 10 days

Another important factor to consider is your training intensity. If you’ve been heavily pounding the pavement, it’s better to taper too much than not enough.

How Often Should You Taper?

You need to pick your races. This is especially crucial if you race a lot, where tapering before every race would leave little time for actual training.

You don’t want to dilute the impact of the strategy. So pick out the big races that you want to go all out for. Aim for only once or twice a season. Then train through the rest.

How to Taper

Tapering doesn’t mean you stop running altogether. Its just choosing quality over quantity.

A study in the Washington Running Report found that runners had the best results when they cut back on easy miles (like the three-mile jog before race day) and focus instead on more intense runs (like the previous Tuesday’s hill repeat workout).

According to Owen Anderson, Ph.D., editor of Running Research News, runners can compute their total interval distance for the tapering week by multiplying their usual weekly mileage by 9%. The result will be your total interval distance for the taper week.

Sounds like a lot of math but it’s actually quite simple. Say you average around 40 miles a week and you have a 10K the following Sunday. Your taper calculations would be: .09 x 40 = 3.6 miles of intervals, or 15 400m intervals

Break these up periodically throughout the week leading up to the race. Take a full break on the Friday and Saturday before the race.

What Tapering Feels Like

Tapering can feel uncomfortable. Well-trained runners may feel antsy, worry about overeating or losing fitness. A tip I’ve found that helps is to focus your energy on visualizing your race. Think about split times, likely competitors and strategies for challenging parts of the course.

A good time to tell how your tapering strategy worked is when you line up for the start. If you’re chomping at the bit—feeling like you really need a run—you’ve tapered correctly.

Want more STACK secrets? See Marathon Runner Meb Keflezighi Shares His Secret for Injury-Free Running and The Secret to Running Faster.

References

[1] Mujika, I. Ñ. I. G. O., & Padilla, S. A. B. I. N. O. (2003). Scientific bases for precompetition tapering strategies. Medicine and Science in Sports and Exercise, 35(7), 1182-1187.

[2] International Journal of Sports Medicine, 1998, Vol. 19, No. 7, pp. 439-446; European Journal of Applied Physiology, 1998, Vol. 78, No. 3, pp. 258-263)