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Hill accelerations

Aim of Session

Climbing session, where on reaching the top maximum intensity is held over the summit

Session description

WARM UP: 15 mins of zone 2, 5 mins zone 3

MAIN SET: Climb the hill in zone 4, and on reaching the summit, power down to maximum effort for 2 mins. Repeat 4 times, 6 mins of easy pedalling in between reps

COOL DOWN: 15 mins easy spin

Physiology

The 2 minutes of maximal effort over the hill will take the body systems into the area of your VO2max, so similar physiology to the 3 minute intervals (towards maximal heart rate and stroke rate so that the body can supply high rates of oxygen to the muscle tissue). However, a critical difference comes from the fact you have already been exercising in zone 4 before starting the maximal effort - this means you will have been stressing the glycolytic system of energy production - that which produces energy from the body's carbohydrate stores and will lead to lactate and hydrogen ions. The muscle fibres will be challenged in reaching maximal powers when in this environment, as hydrogen ions reduce the ability of the muscle fibres to contract. Power output might threrfore be lower than work in a traditional 3 minute VO2max interval. Ultimately, the physiology will be determined by how long the hill of choice is as a) this will change the time you spend in zone 4 before hitting maximum effort and b) have a consequence on the 'work to rest ratio' of the session. A longer hill i.e. more than 4 minutes will push the duration of the work to ~6 minutes, and work will equal rest. This makes the session more 'aerobic', as the work will take longer to recover from, and oxygen uptake and ventilation will stay higher in the recovery. If a shorter hill is used, the rider can exercise more anaerobically as work will be shorter than the 6 minutes of recovery i.e. more complete recovery will mean you can go harder in each rep.

Application for the Rider

As will probably come across in the above discussion, the physiology of this session can be manipulated dependent on the rider's needs: strengths/weaknesses, events to be raced. You will need to talk through with your coach what is the best length hill to use: one that will give equal work to rest (if looking for an aerobic session) or work less than rest (so you can go harder on the climb with more time to recover).

This session is a great one for road racers, mountain bikers and time triallists alike - as all of those disciplines require the ability to push power on descents - an often neglected area in training. We tend to focus on hill climbing, but sometimes the best time to establish a breakaway, get ahead on a single track, or capitalise on speed is to push OVER the summit - a rider can be limited in their ability to keep force production high when their gearing only allows high cadences (which can be the case in high speed time trialling events). A rider will know how different it feels to generate power on the flat compared to on a hill climb - the same is evidenced in downhill work: muscle fibre recruitment is different across all 3 situations as the rider subtly shifts position relative to the bottom bracket.

Practicalities and tips!

  • Find a climb of suitable length and be sure to approach it from the side that will allow a fairly straight descent - this is not a time for technical work, but all out power.
  • Likewise, make sure the descent does not have any oncoming junctions!
  • The climb should not be so steep that you cannot work in zone 4 at a good cadence i.e. 80 to 85rpm
  • Consider your gearing for the climb and think ahead to the transition from zone 4 through to maximal effort. You need to be in a gear that will allow you to not only shift into a higher intensity of effort, but also take into account higher speeds as you crest the hill.
  • Start your effort a) on the climb and b) into the maximal effort at the same landmark each time - this will enable you to compare each interval more easily

Evaluation of the session

  • If the first time out on this session, was your choice of hill a good one to enable the session to run as suggested?
  • How was your work rate in zone 4? Cadence, power and heart rate under control i.e. hard but steady?
  • What did your power peak at in each rep? Was this sustainable over the 2 minutes?
  • How did the set of reps compare power wise a) across the whole of the rep i.e. climb and 2 min effort and b) for the 2 min rep alone?
  • Can the rate at which your HR fell after the effort tell you anything about your recovery?
More in this category: « VO2max intervals Power intervals »