Speed work helps improve lactate threshold, improve V02 max, running economy, and running form. Additionally, you gain mental fitness by learning how to keep pushing when speed workouts get tough. By improving these elements of your fitness you’ll can start to see improvements in your running at all distances and efforts!
There are two main kinds of speed work:
1) Interval workouts which focus on improving V02 max
2) Tempo runs which focus on improving Lactate Threshold
What is V02 Max? The maximal amount of oxygen your heart can pump to your muscles and that your muscles can then use to produce energy
Determined by: maximal heart rate, maximal amount of blood pumped per heartbeat, proportion of oxygen extracted from the blood and used by your muscles
V02 Max is the maximal rate you can produce energy aerobically — the more energy you can produce the faster pace you can maintain
Improving V02 Max can be done by doing interval workouts
There are two types of interval workouts:
- Short Intervals
- Duration: 15 seconds to 2 minutes.
- Focus: Speed, running mechanics, and neuromuscular efficiency.
- Effort Level: Near-maximal to all-out (85% – 100% max effort).
- Recovery: Typically equal to or longer than the work interval
- Long Intervals
- Duration: 3 minutes to 5+ minutes (or 800m to 1600m on a track).
- Focus: Aerobic capacity (\(VO_{2}\) max), lactate threshold, and race-pace stamina.
- Effort Level: Hard but sustainable (about 80% – 90% max effort, or “comfortably hard”).
- Recovery: Shorter relative to the work period, usually partial recovery
- Note: between intervals it is best to keep moving at a slower pace (jogging or walking if needed)
- Benefits of keeping moving during recovery: increased clearance of lactate from your muscles/blood, helping your muscles stay loose/warm, keeping your heart rate and oxygen consumption somewhat elevated so less time is requires to reach optimal zone during next interval
By repeatedly pushing your heart rate to near-maximal levels, intervals force your heart to pump more blood and your muscles to use oxygen more efficiently
What is Lactate Threshold (LT)? The physiological tipping point where your body produces lactic acid faster than it can clear it.
Determined by: your oxygen consumption at that pace (how much oxygen your body uses to produce energy need to run pace) and running economy (how fast you can run using a given amount of oxygen)
Improvements in lactate threshold occur because of decreased lactate production and increased lactate clearance caused by adaptations within muscle fibers
Improving lactate threshold is done by doing tempo runs which are 20-30min runs at a “comfortably hard” pace
- There’s a few ways to determine this pace:
- Heart race: 80-86% of max HR
- Perceived effort: 7-8/10; pace is manageable for a fairly long time (up to an hour)
- Talk test: pace at which you can only grunt a fragmented “yes” or “no” to someone speaking to you
- LT pace is generally 10 to 15 seconds per mile slower than 10K race pace or 20 to 30 seconds per mile slower than 5K race pace **base this on a recent (within last 6 months) race time