The Science Behind Paddling Intervals
Our skeletal muscles, which provide movement for our bodies, are each composed of a mix of muscle fibre types commonly identified as Type I (slow-twitch), Type IIa (fast-twitch) or Type IIx (fast-twitch). Slow-twitch fibres are smaller, more efficient and fatigue resistant (more endurance) as they are better able to utilize aerobic (oxygen) energy pathways, but produce less power and speed. On the other hand, fast-twitch fibres are larger and produce more power and more speed but fatigue more easily. Based on the intensity of the activity being performed, muscle fibres within a muscle are generally recruited in the following order: Type I → Type IIa → Type IIx. What this means is that in order to recruit and train fast-twitch muscle fibres, you must train at higher intensities; otherwise, the slow-twitch fibres within are adequate to meet activity demands without recruiting fast-twitch fibres.
Paddlers depend on slow-twitch fibres for endurance. However, as my exercise physiology professor used to say, “a trained muscle fibre is a more aerobic muscle fibre.” When trained, the Type IIa fibres become more fatigue resistant (albeit still less than Type I). Because they provide greater contractile force than Type I fibres, trained Type IIa fibres allow top-end endurance performance across all paddling distances.
Bottom line: If you’re always paddling at an easy-to-moderate pace TZ 2 then you’re missing out on training the fast twitch fibres and will race below your performance potential. One of the best things about intervals is that you don’t have to do a lot of volume to get a lot of benefit. Like any type of training, “use it or lose it” holds true for training fast-twitch muscle fibres.
Two Paddling Interval Progressions
Here are three paddle interval progressions that you can perform as part of a training session each week over a four-week period to paddle faster in your next ace.
The interval sets are progressed from one week to the next by altering the number of repetitions, duration of each repetition, and/or the rest interval between repetitions.
- ‘ = minutes
- “ = seconds
- TZ 1 RPE 1-2 Very relaxed. Able to carry on a conversation
- TZ 2 RPE 3-4 Working. Feel warmer. Heart rate and respiration up. May sweat
- TZ 3 RPE 5 Hard work. Heart rate and respiration up. Carbon dioxide build-up. Sweating. Breathing hard.
- TZ 4 RPE 6 Stressed. Panting. Sweating freely –RPE 7 Very stressed. Gasping. Sweating heavily.
- TZ 5 RPE 8-10 heavily stressed. Gasping. Sweating heavily.
- VO2max Intervals
VO2max (or maximal aerobic capacity) can be defined as the maximal rate at which an individual can utilize O2 during intense exercise. VO2max intervals are very hard efforts that are typically between three and seven minutes in duration, and represent the maximum amount of time that an individual can exercise at their VO2max intensity.
Performing this type of interval will increase aerobic capacity (body’s ability to use more oxygen) while both decreasing and enhancing tolerance to acidosis (burning feeling in the muscles).
Perform a Paddling session with one VO2max interval set per week (preferably on same day of every week) on flat/ calm water. These intervals are appropriate for pre-competition and competition training periods (starting roughly six to eight weeks out from a goal race).
Week 1 TZ 1 3’/TZ 4 3’/TZ 1 2’/TZ 4 4’/ REPEAT X 4
Week 2 TZ 1 2’/TZ 4 5’ TZ 2 2’/ REPEAT X 5
Week 3 TZ 1 2’/TZ 4 4’/TZ 1 2’/ TZ 4 3’/ REPEAT X 5
Week 4 TZ 1 2’/TZ 4 6’/REPEAT X 5
- Anaerobic Endurance (AE) Intervals
AE intervals are maximal efforts for 30 to 90 seconds that feel VERY, VERY HARD. These intervals are important for the start and finish of a Race but also help to build Tolerance to surging in races and chasing Ocean /wind swells in Distance racing.
Week 1 TZ 1 2’/TZ 5 20”/TZ 3 3’/TZ 5 20”/TZ 2 2’/REPEAT X 5
Week 2 TZ 1 2’/TZ 5 40”/TZ 3 4’/ REPEAT X 7
Week 3 TZ 1 3’/TZ 5 60”/TZ 3 3’/TZ 5 20”/REPEAT X 5
Week 4 TZ 1 2’/TZ 5 20”/TZ 3 5’/TZ 5 40”/REPEAT X 6
Most Paddling races are endurance events so endurance training is a primary focus of any training program. However, if you want to maximize your performance potential, then you must include intervals. Do these intervals progressions over four weeks and be faster in your next Paddle Race.