Basic endurance training

There are six broad categories of training that athletes must use to maximize the potential of the various physiological systems in their bodies. These are:

1. Endurance training
2. Sprint training
3. Race-pace training
4. Recovery training
5. Strength and power training
6. Flexibility training        

Today I'm going to write about endurance training and more specifically about basic endurance training.

Athletes should use three levels of endurance training to achieve their goal of improving endurance. The first level is termed basic endurance training, it is the kind of training that an athlete does at a speed slower than the speed that corresponds to his anaerobic threshold but faster than the aerobic threshold training speed. The second level of endurance training is termed threshold endurance training. An athlete does this kind of training at a speed that approximates his anaerobic threshold. The third level of endurance training is termed overload training, where the swimmers should swim their overload repeats at a speed that is faster than their anaerobic threshold speed.

Basic endurance training involves swimming long distances at moderate speed. The training effects of basic endurance training are:

• Increased stroke volume and cardiac output
• Increased blood volume
• Increase in capacity of pulmonary capillaries
• Improved blood shunting
• Increase in number of capillaries around slow twitch fibers
• Increased myoglobin and mitochondria in slow twitch fibers
• Increased rate of lactate removal from slow twitch fibers 
• Increased rate of lactate removal from blood
• More time available for replacement of muscle glycogen in fast twitch muscle fibers
• More time available for replacement of muscle glycogen in slow twitch muscle fibers 
• More energy provided by fat at all submaximal speeds

When you'll start planning your basic endurance training sets, you should take into account four variables:

1. Set length. 600 yd or m or 8 min and longer. Recommended minimum distances and times of 2000 yd or m and 15 min.
2. Rest interval. 5 to 10 sec for short repeats, 10 to 20 sec for middle distance swims, and 20 to 60 sec for long repeats.
3. Repeat distance. Any distance can be used. Recommended repeats of 200 yd or m and work times of 2 min or longer.
4. Training speed. Sufficient to produce blood lactates greater than 1 and less than 3 mmol/L, slower than threshold speed by 2 to 6 sec for 100 yd or m, heart rates in the range of 120 to 150 bpm or 30 to 60 bpm below maximum, breathing rates faster than resting but not labored, or a perceived exertion of 12 to 14 on a scale of 1 to 20.

 The swimming distances and rest intervals of the first three variables depends on the age and ability of the swimmer. The most efficient way to ensure continued improvement of aerobic capacity is to increase the daily and weekly volume of basic endurance training. To increase the training load gradually, athletes can swim progressively longer repeat distances. Other methods for maintaining an overload are to swim basic endurance repeats at a faster pace or to rest less after each repeat. Swimmers must be careful not to change the nature of the training effect when using these methods. Over time, the repeat speed or lack of rest might produce training intensity at or beyond the anaerobic threshold, which would alter the training effects. The time to apply additional overload can be determined by monitoring training with one or more of the methods metioned at the training speed variable - by measuring blood lactate concentrations, counting heart rates, counting breathing rates, or rating perceived exertions.

Basic endurance training should be stressed early in the season for two reasons. First, basic endurance training will increase the amount of oxygen that can be made available to the muscle fibers later in the season. Second, increasing the rate of fat metabolism will reduce glycogen use during endurance sets so that swimmers will be able to restock muscle fibers more quickly. Both of these adaptations will improve their ability to tolerate greater amounts of the more intense training that they will need to perform later in the season. Basic endurance training should be used extensively during the first 8 to 12 weeks of each new season, making up perhaps 60% to 70% of the total training yardage during that time. After swimmers have increased their aerobic capacity and rate of fat metabolism, the percentage of this form of training can decrease between 50% to 60% of the total, and greater amounts of threshold and overload training can replace it.