Your body needs energy and different levels of exercise causes your body to use energy sources in different ways. Muscles are fueled by three distinct pathways:

  1. Phosphagen System: Known as the ATP-PC (adenosine triphosphate – phosphocreatine). This system provides energy for short-duration, high-intensity activities, such as weightlifting, sprinting, and jumping. It uses stored creatine phosphate and ATP (adenosine triphosphate) to rapidly produce energy.
  2. Glycolytic System (anaerobic): This system provides energy for activities that last longer than the phosphagen system can support, typically up to around 2 minutes of high-intensity exercise. It involves the breakdown of glucose, either from stored glycogen or from the bloodstream, to produce ATP.
  3. Oxidative System (aerobic): This system provides energy for low to moderate intensity activities that last for longer than a few minutes. It uses oxygen to break down carbohydrates, fats, and proteins to produce ATP.

The methods that energy is transported to your muscles are dependent upon the intensity and duration of your paddling. The efficiency of these systems helps determine your paddling endurance capacity.

The following chart illustrates the ways your body gets energy based on the duration of the activity. Longer activities require high amounts of aerobic conditioning and less anaerobic. Whereas shorter activities need more of a balance between the two and short sprints need phosphate system.

Figure 1: Where the fuel comes from for different activity lengths

Figure 1 can be understood by looking at the duration of your activity, say 30 minutes. On the 00:30:00 line you see about 7% of your energy comes from phosphate system, 18% from Anaerobic and the rest, 75%, from Aerobic.

So What?

Good point. Why care? To be well balanced we need to train all 3 systems to make them stronger. This means we need a combination of the following:

  • Phosphate (1 minute sprints, lots of rest)
  • Anaerobic (longer 3-15 minute repetitive sprints)
  • Aerobic (long runs over 30 minutes at high effort).

The trick is to design your training around your goals. If you want to do do sprints, then phosphate and anaerobic is important. If you’re doing longer events then aerobic training needs to be a priority. However all racers need to do sprints at some point in a competition so none of these types of training should be overlooked but you want to proportion them according to your training goals.

Phosphate Training

The phosphate system drives fast muscle contractions. The phosphate system does not use oxygen and due to the few chemical reactions required, it is the fastest pathway for muscle energy. The phosphate system does not use glucose, or produce lactic acid, hence it supplies anaerobic alactic energy. Muscle contractions are controlled locally by adenosine triphosphate (ATP), which is broken down into adenosine diphosphate (ADP) and energy. You’ll see ATP and ADP mentioned often in sports metabolism.

Muscles have an internal store of ATP that can be called upon for short bursts of maximum effort, up to approximately 3 seconds. The phosphate system then kicks in, and can provide energy for maximum effort for another 12 seconds.

The only way to increase and improve your ATP storage and phosphate system response is with hard, short sprints, alternated with periods of complete rest bringing your heart rate near resting rates. Several months of sprint training will increase this capacity by 25% to 50%.

This type of training is known as High-Intensity Interval Training (HIIT). HIIT sessions should last no longer than 30 seconds and require maximum effort. Examples of phosphagen system training for paddlers include:

  1. Short sprints: Paddlers can perform short sprints of 10-20 seconds at maximum effort, followed by a rest period of 2-3 minutes. This can be repeated for several sets.
  2. Plyometric exercises: Paddlers can perform explosive exercises such as jump squats, jump lunges, or box jumps, which engage the muscles of the lower body and recruit the phosphagen system.
  3. Resistance training: Paddlers can perform heavy resistance training exercises such as deadlifts, squats, and bench presses, which engage the muscles of the entire body and require maximal effort.

Anaerobic Training

When carbohydrates or glucose are burned in the muscles they produce lactic acid. This waste product has to be processed quickly and efficiently by the liver. The liver has the ability to convert this acid back into glucose for the muscles to use again. Your livers ability to process this lactic acid is known as the lactate threshold. This is often something monitored in professional athletes while they train.

Lactic acid production chokes your anaerobic power over time. Increased muscle acidity, called acidosis, damages the muscle cells and leaks lactate into the blood. Additionally this acid buildup decreases aerobic endurance. Muscle contractions at very high lactate concentrations become more difficult because of a lack of ATP.

Remember that burning pain as you push the last lap on a 1 mile sprint? That wall where everything suddenly starts to feel heavier and heavier is do to the acidosis and lack of ATP or electrolytes (ion depletion). Here’s how muscles get tired: and from the same author how muscles grow via hypertrophia:

Hard anaerobic exercise often requires days for the body recovers sufficiently to regain full aerobic capacity. Without sufficient recovery between bouts of hard anaerobic exercise, both aerobic and anaerobic endurance capacity decrease considerably, leading to a number of problems referred to collectively as over training.

Recovery time, from 24 hours to as much as 96 hours, is necessary after hard anaerobic workouts. A good training program that includes anaerobic intervals, high intensity “threshold” exercise or tempo training, or racing requires recovery time planning to avoid over training effects on the anaerobic system.

  • Resting about 25 minutes to remove half the accumulated blood lactate. Roughly 90% of lactate is removed after about 1 hour of rest.
  • Always cool down. 20 minute light cool-downs following a race or hard workout accelerate the removal of lactate greatly. Almost 90% will be removed in 20 minutes of light easy exercise.

Anaerobic training requires periods of intense workouts in 3 to 15 minute intervals with some recovery time in between.

To train the anaerobic or glycolytic system, paddlers can perform high-intensity exercises lasting between 30 seconds to 2 minutes with shorter rest periods in between. This type of training is known as High-Intensity Interval Training (HIIT). Glycolytic system training for paddlers can include:

  1. Sprints: Paddlers can perform sprints with resistance or against wind or current, where they aim to maintain high-intensity effort for 30-60 seconds, followed by a rest period of 30-60 seconds. This can be repeated for several sets.
  2. Circuit training: Paddlers can perform a series of exercises in a circuit with minimal rest between each exercise. Examples of land based exercises can include squats, lunges, burpees, push-ups, and rowing machine sprints.
  3. Tabata training: Paddlers can perform 20 seconds of high-intensity effort, followed by a 10-second rest period, repeated for 5+ rounds, building more sets as needed.

Recovery time from a predominately long and hard anerobic activity takes up to 48 hours to replenish glycogen in the liver. Muscle glycogen can be replenished in a few hours. Long workouts (2 hours or longer) should be followed by a recovery day of light exercise, or a strength-training day. If you are training for a very long event (15+ miles), it is not uncommon for athletes to train 3 hours followed the next day by 5 hours. This helps train your body for partial recovery times like those long events where recovery time is during the race.

Aerobic Training

The aerobic system, commonly associated with oxygen and called the “oxygen” system, utilizes fats (in particular, triglycerides) and sugar (in particular, glycogen) to fuel your muscles. This conversion produces ATP for your cells us use as energy.

Exercise allows you to train the muscles’ metabolic systems to use energy more economically. The number and density of mitochondria in the muscles increase with proper training, providing more “engines” to burn fat and glucose. This in turn increases the efficiency of the metabolic pathways allowing a well-trained athlete to oxidize fat for a longer time.

The body stores enough carbohydrate in the muscles and the liver to provide about 90 minutes of energy. When your carbohydrate stores are depleted, fat burning increases and the ability to sustain your level of effort decreases – fat oxidation always requires a small amount of carbohydrate to keep contractions full strength. To avoid fading or hitting a wall glycolysis can be extended by having carbohydrate rich drinks or snacks.

To improve the aerobic system, paddlers should focus on exercises that increase their endurance capacity. Here are a few ways that paddlers can train their aerobic system:

  1. Steady-state paddling: This involves maintaining a steady pace of paddling for an extended period of time, typically 20 minutes or more. This type of training can help improve cardiovascular fitness and endurance.
  2. Long-distance paddling: Paddlers can gradually increase the distance of their paddles, focusing on maintaining a steady pace throughout the session. This type of training can help improve endurance and build mental toughness.
  3. Interval training: Paddlers can perform intervals of high-intensity paddling, followed by a period of rest or lower-intensity paddling. For example, they could paddle at a high intensity for 30-60 seconds, followed by a rest period of 30-60 seconds. This type of training can help improve both the aerobic and anaerobic systems.
  4. Cross-training: Paddlers can engage in other forms of aerobic exercise such as running, cycling, or swimming to improve their overall aerobic fitness.

Aerobic energy levels can be increased. The body adapts to the stress of training and will increase the density of aerobic muscle mitochondria from 3.5% of muscle mass to as much as 5% of muscle mass. Years (3-4) of extensive aerobic training can increase aerobic endurance capacity by approximately 50%.

Other changes that occur over time include increased mitochondria which generate most of the chemical energy needed to power the cell’s biochemical reactions along with blood vessel capillary growth for better blood circulation to tissues. So in general when developing aerobic capacity for paddling, you need to paddle with your heart rate in the aerobic zone to focus development in the critical muscle areas for aerobic energy. This is known as training specificity. Cross-training won’t by itself increase paddling aerobic fitness, but it will increase cardio-pulmonary efficiency that is sometimes hard to increase with just paddling alone.

Why Warm Up?

Always warm up. It takes about 3 minutes before the heart, lungs, and circulatory system are fully functioning and for the aerobic system to be fully engaged.

  • Increased blood flow: A warm-up helps increase blood flow to the muscles, which can improve the delivery of oxygen and nutrients to the working muscles.
  • Improved muscle elasticity: A proper warm-up can improve muscle elasticity and flexibility, making the muscles more pliable and less susceptible to injury.
  • Enhanced muscle activation: A warm-up can activate the muscles that are going to be used during the training or race, improving their readiness to perform.
  • Improved mental focus: A warm-up can help athletes get mentally focused and prepared for the physical demands of the training or race.
  • Reduced risk of injury: By preparing the body for the physical demands of exercise, a warm-up can help reduce the risk of injury.
  • Improved performance: A proper warm-up can help improve performance by enhancing the athlete’s physical and mental readiness to perform.

Why Cool Down?

An athlete should always cool down after exercise to gradually bring the body back to a resting state. A proper cool down can provide several benefits, including:

  • Preventing blood pooling: During exercise, blood flow is directed to the working muscles. When exercise stops suddenly, blood can pool in the veins of the legs, which can cause dizziness or fainting. A cool down helps maintain blood flow and prevents pooling.
  • Removing waste products: During exercise, waste products such as lactic acid can build up in the muscles. A cool down helps remove these waste products from the muscles, which can help reduce soreness and stiffness.
  • Reducing heart rate: A cool down can help gradually reduce the heart rate, which can help prevent blood pressure from dropping too quickly.
  • Promoting relaxation: A cool down can help promote relaxation and reduce stress levels, which can be beneficial for both physical and mental recovery.

Studies have shown that a cool down can significantly reduce the accumulation of lactic acid in the muscles, which can help improve recovery and reduce muscle soreness. One study found that a 10-minute cool down after high-intensity exercise reduced blood lactate levels by approximately 23% compared to stopping exercise abruptly. Another study found that a 15-minute cool down after high-intensity interval training reduced blood lactate levels by approximately 20%.

A cool down should typically last between 5 and 15 minutes, depending on the intensity and duration of the exercise. It could include low-intensity exercise such as jogging, cycling, or walking, followed by stretching exercises to help improve flexibility and range of motion. Overall, a proper cool down can help athletes recover faster and reduce the risk of injury.