For the last 10 years or so, fitness-minded runners have profited tremendously by carrying out vVO2max workouts, but swimmers have been loathe to try them. That's a shame, because vVO2max sessions can have a tremendously positive impact on overall swimming fitness and swimming performances. vVO2max workouts are also easy to plan: Simply swim as far as you can in five minutes, and measure the distance traveled in five minutes. For subsequent workouts, you can swim one-minute intervals over one-fifth of the distance covered during the five-minute test or 2:30 intervals over half the distance. Every four to six weeks or so, take the five-minute test again to determine your new vVO2max. Full details and updates about vVO2max training, including how to supplement it with other kinds of work, are now provided in the pages of Swimming Research News.

Let's say you have scheduled an interval workout for yourself which consist of 10 100 meter work intervals, with equal-in-time-duration recoveries. Is it better to carry out those work intervals one after another, with no break at all, or would it be perferable to break the session down into two sets of five intervals, with a nice break in between?

There is good arguments for each strategy. For example, taking a break in the middle of the workout might allow the final intervals to be carried out with higher quality. On the other hand, not using the break might lead to higher overall rates of oxygen consumption (because the rate of oxygen consumption would not fall during a break) and loftier lactate levels (which could stimulate greater enhancements of lactate threshold). What does research say?

Investigations carried out with swimmers on this topic are non-existent, so we'll have to turn to an excellent recent study with runners carried out by Dr. Magaly Tardieu-Berger and colleagues from the Motricity, Interactions, and Performance Laboratory in Nantes, France and the Physiology and Biomechanics of Exercise Laboratory at the University of Rennes in France. In the new piece of research, 11 endurance-trained subjects aged 15 to 18 tried out the two interval-training techniques (1). The average VO2max of the athletes was 62.6 ml'kg-1 min-1, and mean max heart rate was 196 per minute.

First, the young runners were tested for MAV (maximal aerobic velocity), as follows: Cones were placed at 50-meter intervals along a track (inside the first line), and a required running pace was established by one of the researchers, who was equipped with a whistle and a chronometer. The researcher made a brief whistle each time a subject had to pass by a cone in order to maintain a specified speed.

A longer whistle signaled to each runner the need to increase pace. Before the MAV test begun, each athlete warmed up with 10 minutes of continuous jogging and then carried out five minutes of stretching activities. The initial speed for the MAV exam was 12 kilometers per hour (a tempo of two minutes per 400 meters), and the running velocity was increased by 1 km per hour every two minutes. Naturally, the runners eventually became too exhausted to complete a two-minute stage, and the speed associated with the last completed stage was judged to be MAV. However, if the velocity at exhaustion was maintained for at least one minute (within the final two-minute stage), then MAV was judged to be equal to the velocity during the previous stage plus .5 kilometers per hour (a "half-step" in speed).

For more information about this MAV-measuring technique, please see references 2 & 3 below. Here is a table of the speeds used in the test:

VELOCITY (km/hour)                                                              TEMPO (seconds per 400)

               12                                                                                                          120

               13                                                                                                          111

               14                                                                                                          103

               15                                                                                                            96

               16                                                                                                            90

               17                                                                                                            85

               18                                                                                                            80

               19                                                                                                            76

               20                                                                                                            72

The workout under consideration (to compare the two basic strategies) was a basic one: The runners were asked to hit (after a warm-up, of course) 30 second work intervals at a speed of 110 percent of MAV, with 30-second recoveries at a jogging pace of about 50 percent of MAV.

In one case, the athletes simply kept on going, without any break, completing as many work intervals as they could before exhaustion set in (or before they could no longer maintain 110 percent of MAV for the required 30 seconds).

On another occasion, the runners completed six work intervals, with 30-second recoveries (the first series), and then enjoyed a nice four-minute "mixed" recovery (jogging, walking, resting) before embarking on a second series of 30-30 intervals. This pattern continued, with four-minute recoveries occurring after every sixth rep until the athletes decided they could not continue (or they were unable to hold 110-percent-of-MAV tempo).

The order of these two key workouts (the no-set workouts vs. the set-of six-reps sessions) was randomized, and a similar warm-up (consisting of 10 minutes of jogging at eight-minute per mile pace (12 km/hour), five minutes of stretching, three short "strides," and two minutes of rest) was conducted prior to each session.

To learn more about Should You Use Sets of Swim Intervals for swimming (the full article can be read by purchasing Vol. 2 Issue 1) and many more swimming related topics. Simply click on the Back Issues link, select the volume and issue number from the drop-down menu, or enter any subject you wish to learn more about. A subscription to Swimming Research News is another way to receive valuable information.
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