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How does strength training affect the determinants of endurance performance?

Two of the most common methods of strength training are heavy strength training and explosive strength training. Both of these methods can improve endurance performance, but both promote different training adaptations. Heavy strength training is designed to increase or maintain the maximal force that can be produced by the muscles and is typically characterised by lifting loads that allow for 1 – 15 repetitions. Explosive strength training is typically involves accelerating lighter loads (sometimes only body weight) at maximal speeds.

One of the most commonly reported ‘predictors’ of endurance performance is maximal oxygen consumption or V̇O2max. Measured in a controlled environment in a laboratory, large V̇O2max values have been associated with success in endurance-based sports. However, it is important to remember that the winner of a race might not be the competitor with the highest V̇O2max. Although there is a large genetic component to determining an athlete’s V̇O2max, it is ‘trainable’ and can improve following well-structured training. Interestingly, there is no evidence to suggest that adding strength training to an endurance athlete’s training programme will increase their V̇O2max more than endurance training alone. Therefore, strength training must improve performance by improving other factors associated with endurance capacity.

Economy, the energy cost of movement, is another important determinant of endurance performance. In much the same way as no two cars have the same fuel economy, there are large differences in the exercise economy between athletes, even if their same V̇O2max values are the same. Improvements in exercise economy are likely to be mirrored by improvements in endurance performance. Heavy strength training has been shown to improve economy in recreational level and well-trained cyclists. One study showed an improvement in economy after 3 hours of moderate intensity cycling following a period of heavy strength training.

The maximal speed or power output that can be sustained for a prolonged period of time (40 – 60 minutes), is known as the functional or lactate threshold. This threshold intensity has been shown to be extremely useful in predicting endurance performance in cyclists. Data on improvements in functional threshold following strength training, are equivocal. There is some evidence that including heavy strength training will improve this functional threshold, while other studies show no change in this performance parameter. However, it is worth noting that there is no evidence that strength training negatively affected functional threshold.

Endurance performance can also be predicted from a cyclist’s peak power output (PPO), which is the intensity associated with their V̇O2max. The inclusion of strength training to cyclists’ training programmes has been shown to improve their PPO and the time they are able to ride at this maximal intensity. However, it is interesting to note that the addition of explosive strength training to cyclists’ training regimes, does not appear to improve their PPO.

Performance in mass start races can often be affected by getting into a good position at the start of the race. An Olympic Cross-Country race is a great example of this, with riders fighting it out to be in the front positions when they reach the first single track section. Failure to do so could result in riders getting stuck at bottle necks or behind slower riders. A good start requires riders to generate a high power output for a short period of time. This attribute is not limited to the start and generating high power outputs for relatively short periods of time could allow riders to get passed slower riders, break away in an ultra-marathon or win the sprint in a mass start road race. Heavy strength training has been shown to increase the maximal power output in well-trained cyclists.

All of the research on strength training and cycling performance appears to support the inclusion of maximal strength training as part of your training programme. Strength training improves endurance performance by reducing the energy cost of the exercise, delaying fatigue, improving anaerobic capacity and maximal force production.

What should you look for in a strength training programme?

When including strength training as part of your preparation, it is important to remember to decrease the volume of your endurance training. Simply adding strength training to an already high-volume training regime, may not result in improvements in performance. The strength training exercises should target the muscles groups used in cycling and the movements should be similar to the sport-specific movements of cycling. In cycling, the muscles around the hip, knee and ankle joints are required to work together in order to deliver force to the pedal. Heavy strength training appears to be superior to explosive strength training in improving endurance performance in cyclists. Maximal strength can be increased gradually during the ‘strength’ and ‘base’ phases of your training programme with two sessions per week. Cyclists should try and include multi-joint exercises such as squats, deadlifts or the single-leg versions of these exercises.

During more intense phases of training, when strength development is not the main goal, one session of explosive-type strength training should be sufficient to maintain the adaptations made previously. A good example of a cycling-specific explosive exercise is to warm up for 10 minutes on a stationary bike in the gym. Follow this with five repetitions of the following:

  • Cycle for 30 seconds against a high resistance at a low cadence (60 – 70 rpm)
  • Follow this with 20 explosive step-ups on a 40 cm box
  • Complete the step-ups on your right leg before moving to the left
  • Recover for 2 minutes and then repeat
  • Cool down for 10 minutes

It is important to remember that, just like your endurance training, your strength training should be individually tailored to your individual strength level. The load of your exercises can increase as your force capabilities improve. However, before you begin any strength training programme, it is advised that you learn how to perform the exercises correctly. Learning how to perform the exercises correctly with lighter loads, can prevent injury when heavier loads are used later. Consult a qualified strength and conditioning specialist at the Sports Science Institute of SA or a similar practice to assist you.