Sub-Maximum Heart Rate Training Is The Workout of the Week

Jul 12, 2014; Athens, GA, USA; Michael Phelps warms up prior to the Saturday finals of the Bulldog Grand Slam at Gabrielsen Natatorium. Mandatory Credit: Kevin Liles-USA TODAY Sports

By Ronald Hehn, Concordia College Head Coach

PHOENIX, Arizona, July 16. SUB-Maximum Heart Rate Training is an effective way to increase the cardiovascular capacity of both non-competitive and competitive swimmers. Sub-Maximum Heart Rate Training determines the duration of rest according to the heart rate of an athlete. The athlete’s heart rate must be less than a fixed amount in order to conclude the period of rest, and must not exceed a fixed amount while swimming. Sub-Maximum Heart Rate Training intends to condition the aerobic and sub-aerobic capacity of the athlete.

Traditional heart rate training requires the athlete to maintain a minimum heart rate during a segment of a set. For example, 6×50’s “good effort” should maintain a minimum heart rate above 140 beats per minute; if the athlete does not satisfy the minimum heart rate during the segment, effort must be increased. A fixed interval determines rest based on duration of the swimming portion. That is, as the athlete fatigues and slows, the duration of rest becomes shorter. This phenomenon may not be conducive to successful completion of the segment.

On the other hand, a Sub-Maximum Heart Rate Training requires the athlete to maintain a heart rate below 160 beats per minute during the swimming portion; the duration of rest is determined by the amount of time required for the heart rate to drop below 140 beats per minute. The anaerobic threshold is determined by the amount of oxygen consumption required to satisfy the body’s demand. Aerobic activity utilizes oxygen to generate energy via the heart; anaerobic activity generates energy without oxygen via the liver. Consequently, Sub-Maximum Heart Rate Training can reduce the stress on the liver and shift the conditioning stress to the heart.

The goal of Sub-Maximum Heart Rate Training is to achieve faster or equivalent times at a lower heart rate. It’s not how fast you can swim at a maximum heart rate; it’s how fast you can swim the lowest heart rate possible. Instead of demanding increasingly more work from the body in order to increase results, the body may be conditioned to produce faster results at an equivalent or lower heart rate. Conditioning the heart to efficiently consume oxygen is fundamental to increasing an athlete’s cardiovascular capacity.

Heart rate is determined by the body’s demand for oxygen. Oxygen debt increases heart rate; heart rate increases in order to compensate for insufficient available oxygen. Once the demand for oxygen exceeds supply, energy is produced anaerobically. The capacity of the body to efficiently utilize oxygen in order to maintain heart rate is a good indicator of overall fitness.

In a group setting, there is an opportunity for competition amongst all ability levels. Less-skilled yet more-conditioned athletes may challenge the faster but less-conditioned athletes. The conditioned athlete may be able to overcome their speed-disadvantage with a shorter-duration rest period opposed to their less-conditioned, faster competitor. To increase specificity (and prevent cheating), use heart rate monitors.

*All Intervals Posted On The Workout Are Approximate*

Sub-Aerobic Heart Rate – Heart rate up to 140 beats per minute; Heart primarily generates energy from fatty acids.

Aerobic Heart Rate – Heart rate in the range of 140-160 beats per minute; “good effort”; aerobic metabolism; Heart primarily generates energy from respiration (i.e. oxygen; breathing).

Anaerobic Threshold – Heart rate in the range of 160-180 beats per minute; “Better Effort”; metabolism transitions from aerobic to anaerobic.

Oxygen Debt – Occurs when the demand for oxygen becomes more than is available; anaerobic metabolism; Liver primarily generates energy from glycolysis.

The Workout
Respiration Interval Set: Rest is determined by a specific amount of oxygen intake (i.e. breaths); oxygen intake during rest is determined by a fixed amount of Roberts (Experts: try fixed Stroke Count). In this case, increased frequency of respiration does not result in additional oxygen intake and the onset of fatigue is compounded by reducing the duration of rest; thus, this activity promotes controlled rather than frequent respiration. Oxygen debt may occur, thus slightly elevating the heart rate. The athlete must record the duration of swimming. The goal is to minimize the duration of swimming regardless of duration of rest. The first round is swum freestyle; the second round is choice of kick.

Sub-Maximum Heart Rate Interval Set: – The duration of rest is determined by the amount of time it takes for heart rate to drop below a fixed maximum amount. Heart rate must not exceed 160 beats per minute in order that oxygen debt is avoided; heart rate should stay as close to the fixed maximum amount as possible. Consistently monitor heart rate and record the duration of rest. The goal is to decrease the duration of rest regardless of the duration of swimming. The first round is swum choice of stroke; the second round is choice of kick.

Traditional Interval Set: The duration of rest is dependent on the duration of the swimming. If the athlete swims faster, more rest is earned; if the athlete swims slower, less rest is earned. Consistent duration of swimming yields consistent duration of rest. The goal is to decrease the duration of both rest and swimming regardless of heart rate. First round is swum freestyle; second round is swum choice of stroke.

Respiration and Heart Rate Interval Set: – The duration of rest is determined by the heart rate given a fixed amount of oxygen intake. Oxygen intake is specified by an amount of Roberts to be performed. Heart rate must be monitored in order to determine the remainder of the duration of rest; the next repetition must not begin until the heart rate has dropped below the fixed maximum amount. The goal is to decrease the duration of rest following the fixed amount of Roberts. Odd rounds are swum freestyle; even rounds are swum choice of stroke.

Ronald Hehn is entering his second year as head coach at Concordia, and is the founder of the DakotaSota Swim Club in Fargo. Hehn had an impressive collegiate career as a All-American at Indiana University, and also swam at both the 2008 and 2012 U.S. Olympic Trials. To see more from Hehn, check out his swimming workouts Facebook page.