I've known for a while that the only way to be a faster walker is to practice walking faster. (Paraphrasing Dave McGovern.) I also know that if you do the exact same workouts every day, you will never get stronger. Knowing and doing are two different things.
Today I started doing speed workouts and plan to continue doing them once a week as part of my regular workouts.
Getting my shin muscles properly warmed up has been a problem lately, so I did a mile at a SLOW 15:45 pace with good racewalking form to try to warm up. The sprints were 1/4 mile and I did 6 reps with 2 or 3 min rests in between, depending on how my shins felt, with a half-mile cool down. My sprint times were: 3:18, 3:26, 3:22, 3:13, 3:15, 3:29 with 7:26 for the last half mile.
Despite the warm up, my shins were still tight during every sprint. During my slower times, I even felt pretty stiff as if it was an effort to get my legs to go that fast. I stretched pretty good when I finished and will stretch a few more times over the next day or so. (My shins really need it!)
OK, it is only wishful thinking, but if I were to walk an entire mile as fast as my fastest 1/4 mile sprint, we're talking a 13-min mile! I know the speed workouts will work, and I'm sure I'll be there someday soon.