The 5k

Taken from The Competitive Runner’s Handbook, by Bob Glover and Shelly-Lynn Florence Glover. 
            The 5k issues this special challenge:  too short to relax and too long to sprint.  You’ll be running at close to your maximum aerobic capacity (about 95%) and slightly above your lactate threshold.  At this intensity there isn’t much room for pacing errors.  The goal is getting to the finish line before lactic acid takes control of your body.  If you start too fast or surge too quickly, you’ll soon be running too slowly; your muscles will accumulate lactic acid very quickly.  But if you start too slow or lose contact with your peers, it isn’t easy to get back on goal pace or to catch competitors.
            Lining up in the right spot is crucial.  Starting out too fast up front risks getting stampeded and embarrassed by the faster starters behind you, or getting pulled out too fast by the speedsters ahead.  Starting too slow back traps you behind slower starters, costing precious seconds.  Line up aggressively, but not foolishly.  Be alert and ready to go when the starter sets you off.  Start no more than 5 to 10 seconds per mile faster than you want to average.  A good bet is to start at the pace you think you can average and pick it up a little along the way if you feel good.  The start-slow-and-pick-it-up-later strategy works better for races longer than 5k.  It’s crucial to keep pushing a steady pace while monitoring your body signals.  Slack off, and you’ll fall off pace.  But if you push the pace too much at any point in the race, you’ll crash and burn.  Racing 5k requires constant concentration.  Lose it for a few seconds and you’ll add a few seconds to your finishing time.  Unlike longer races, where you strive to improve by minutes, 5k improvements come in seconds—so every second counts that much more.  Here’s the value of running a few 5k before your peak effort:  You achieve perfect race pacing and concentration with practice.
            I break the 5k mentally into four segments:  first-, second-, and third-mile marks, and the finishing tenth of a mile.  During the first mile, find your rhythm; settle into a steady, strong pace.  Hit the 1-mile mark at or slightly faster than race goal pace.  In the second mile, pick up the effort slightly to keep on pace.  Find a runner or a pack of runners going your pace and hang with them.  Let them pull you along.  Push a little more the third mile to stay on pace and to move up a few places.  Focus on good form.  With about 400 to 600 yards to the finish, gradually accelerate.  Pick out other runners as targets.  At the 3-mile mark, envision the last turn at a track workout, switch to all-out gear, and kick in over the last tenth of a mile to beat the clock and your competition.  One of the perks of 5k racing is that you can race often, producing plenty of opportunities to test different pacing and race tactics.
Here’s the biggest sin in racing.  “But I was feeling so strong the first mile.”  A fast early pace is the reason most runners slow over the second half.  As pace starts to slip away, so does confidence, particularly if many runners pass you.  As you slip mentally you slow even more.
            The majority of runners in every race start too fast.  Joe Henderson a running writer for three decades has said, “A super-fast start isn’t ‘money in the bank’.’  It’s a severe drain on limited reserves.  Exercise physiologists have estimated that every second faster than level pace in the first half of the race costs a second or two at the end; 2 seconds cost you 4 more; 3 seconds slows you by…. Well, there is a geometric progression.”  And the longer the race the longer you will suffer.
            David Costill, Ph.D., explains in Inside Running, “The primary source of energy during the early stage of a race will be the glycogen stored in the muscles.  If the pace is unusually fast in the first few minutes, the quantity of glycogen used will be markedly greater and the muscles’ stores will be seriously depleted.  At the same time, the by-products of rapid glycogen breakdown may result in a large production of lactic acid, which increases the acidity of muscle fibers.  Proper pacing can minimize the threat of glycogen depletion and lessen the chance of premature exhaustion.”  Start too fast in a short race and “the Bear jumps on your back” as lactic acid builds up; start too fast in a long race and you’ll “hit the wall” due to glycogen depletion.