Volume vs Intensity

Which is more important for improving race performance in endurance athletes, the volume of training or the intensity of training? It’s obvious that both play a role in racing well. But athletes tend to place a lot of value on volume than on intensity. I’ve yet to hear an athlete when asked how training is going respond by talking about intensity. The answer is almost always based on volume (“I rode 200 miles last week.”) But given the choice, which should you place more emphasis on when making decisions about your training?

Before attempting to answer these questions let’s define the terms. Volume is the product of duration and frequency. Duration is how long a workout lasts. Frequency is how often workouts are done. Volume is usually expressed in terms of weekly, accumulated training time or mileage. Intensity for the purpose of this discussion refers to training done at or above the anaerobic threshold (also sometimes called lactate threshold, ventilatory threshold, or functional threshold). Assuming that you are preparing for an event that takes about one hour or less to complete at a maximum, sustainable effort, this intensity is about race intensity. For athletes competing in events that last longer than about one hour, training intensities at and above AT is more challenging than race effort. This is not to say that athletes training for longer events should not train above the AT. It is quite common, especially for elite and well-experienced athletes.

Let’s get back to the original question: Will volume or intensity have a greater impact on your race performances? There is very little research on this matter, but what there is seems to be in agreement. Let’s examine two of these for some insight.

In a German study 17 experienced runners steadily increased their volumes from their normal 50 miles per week to 105 miles per week over a four-week period (1). All of these runs were done at about marathon pace or slower (2mmol/L lactate) One year later they allowed the researchers to tinker with their training again. This time they nearly doubled the amount of time they trained at high intensity, over a four-week period again. With increased intensity they improved on four measures of performance from 5% to 17%. Increased volume produced no significant improvements in the same metrics.

In another study of swimmers conducted by David Costill, PhD at Ball State University it was found that increasing swim training volume from three hours per day to four per day and increasing swim weekly workouts from five to six sessions provided no greater benefits than training 60 to 90 minutes per day for five days per week (2).

Does this mean you should keep your training volume low while jacking up intensity year round? Not at all. When you have been training with low volume and low intensity for some period of time, as when in the season-ending “transition” period, gradually increasing the stress load by boosting volume is probably a wise move (3,4). This will help to prevent injury by fortifying soft tissues before commencing with higher-intensity training later.

During the Base period it is common in the classic/linear periodization model to increase the volume of training while also much more gradually increasing the intensity. In Base 1 I have my athletes training a considerable amount in zone 2. In Base 2 they add training volume in zone 3. And by Base 3 they are also training in zone 4. This is typical for all of my clients regardless of the events for which they are training. In the Build period the training becomes increasingly specific to the demands of their first A-priority race of the season, especially the intensity of those workouts.

So what’s the bottom line? The intensity of one’s training is a better predictor of performance than the volume of training although some mix of both is necessary for success.

References
Lehmann, M., et al. 1996. Unaccustomed high-mileage vs intensity training-related changes in performance and serum amino acid levels. Int J Sports Med 17(3):187-192.
Costill, D.L., et al. 1991. Adaptations to swimming training: Influence of training volume. Med Sci Sports Exerc 23:371-377.
Gomes, P.S. and Y. Bhambhaniy. 1996. Time course changes and dissociation in VO2max at maximum and submaximum exercise levels as a result of training in males. Med Sci Sports Exerc 28(5):S81.
Fry, R.W., et al. 1992. Periodisation of training stress – a review. Can J Sport Sci 17:234-240.