Bang For Your Buck

One of my favorite books on running is The Science of Running by Steve Magness. The first part of the book lays out what the science says and the second part what the leading coaches do… and it is not always aligned.

The fact is that individual response to training stimulus varies and therefore control group averages only tell part of the story. 

We can see that there are many different approaches to achieving running performance gains from leading coaches:

• Keith & Kevin Hanson - High volume “slow” milage.

• James Li - Less miles more intensity.

• Renato Canova - Starts at the extremes and works to the middle race intensity.

• Gjert Ingebrigtsen - High intensity and high volume.

• Steve Magness - All in the mix - all intensities in the mix throughout the training process.

So how do you know if the plan you pulled off the internet or the one given by your coach is the most appropriate for you? The simple answer is that you don’t and that you need to take personal responsibility to monitor your response to different training stimuli.

One point of contention is the relevance of High-Intensity Interval Training (HIIT) which is a popular and often debated method in endurance training programs. Here, I will delve into the role of HIIT and present different viewpoints and arguments from leading researchers and practitioners.

Role of HIIT in Endurance Training Programs

HIIT involves short bursts of intense exercise followed by periods of rest or low-intensity exercise. It is praised for its efficiency and effectiveness in improving various physiological markers, including VO2 max, lactate threshold, and mitochondrial density.

Viewpoints and Arguments

Proponents of HIIT

1. Dr. Martin Gibala:

   • Efficiency: Gibala's research highlights that HIIT can provide similar, if not superior, cardiovascular and metabolic benefits compared to traditional moderate-intensity continuous training (MICT) in a fraction of the time.

   • Adaptations: HIIT promotes rapid physiological adaptations, such as improved mitochondrial function and oxidative capacity, which are crucial for endurance performance.

   • Practicality: For athletes with limited time, HIIT offers a practical alternative to long, steady-state sessions.

2. Dr. Stephen Seiler:

   • Polarized Training Model: Seiler advocates for a polarized training approach, where HIIT is integrated into a program that also includes a significant amount of low-intensity training. This combination is believed to maximize endurance performance while minimizing the risk of overtraining.

   • Balance: While emphasizing the importance of HIIT, Seiler also cautions that it should be balanced with sufficient low-intensity training to avoid excessive fatigue and injury.

Critics of HIIT

1. Dr. Phil Maffetone:

   • Overtraining and Injury Risk: Maffetone argues that frequent HIIT can lead to overtraining, increased injury risk, and burnout, especially in less experienced athletes [See Note]

   • Aerobic Base: He emphasizes the importance of building a strong aerobic base through low-intensity training, suggesting that too much high-intensity work can compromise long-term endurance development.

2. Dr. Stephen Cheung:

   • Individual Differences: Cheung highlights that the response to HIIT can vary significantly among individuals. Some athletes may thrive on high-intensity work, while others may experience negative effects such as increased stress and poor recovery.

   • Training Periodization: He suggests that HIIT should be carefully periodized within a training program, with periods of high-intensity work followed by phases of recovery and lower intensity to ensure optimal adaptation and performance.

Note: I think there is something in this. If you are new to running or coming back from a long layoff it takes time to build a running body that can fully benefit from intensity. This is an extract from Coach Gordo Bryns' Endurance Essentials...

Over 18-24 months you build a Core Program of:

• 4 days running per week, nearly all Easy/Steady

• A long run, most weeks

• Supplemental cross training

• Strength training

• Daily mobility work

• Shorter duration races & benchmark sets

You are going to be remodeling your heart, your muscles, and your connective tissues. Consistency over time is what it takes.

Balanced Perspective

1. Dr. Veronique Billat:

   • Integrative Approach: Billat advocates for an integrative approach where HIIT is used strategically within a broader training framework. She suggests varying the intensity, duration, and frequency of HIIT sessions based on the athlete's training phase and individual response.

   • Specificity and Variation: Incorporating different types of HIIT (e.g., long intervals, short sprints) can target various physiological systems and prevent monotony and overuse injuries.

2. Dr. John Hawley:

   • Metabolic Health: Hawley points out the broader benefits of HIIT beyond just performance, including improved metabolic health, insulin sensitivity, and cardiovascular function.

   • Periodization and Monitoring: He emphasizes the importance of careful periodization and monitoring of HIIT sessions to ensure they are beneficial and not detrimental to overall training goals.

Practical Recommendations

• Frequency: For most experienced endurance athletes, integrating 1-2 HIIT sessions per week within a balanced training program is recommended.

• Intensity and Duration: Varying the intensity and duration of intervals can help target different physiological adaptations and reduce the risk of overtraining.

• Recovery: Adequate recovery between HIIT sessions is crucial to avoid cumulative fatigue and injury.

• Monitoring: Using tools such as heart rate variability, perceived exertion, and performance metrics can help monitor the athlete's response to HIIT and adjust the program accordingly.

In summary, while HIIT is a valuable tool in endurance training, its application must be individualized and balanced with other training modalities to maximize benefits and minimize risks. The debate among experts highlights the need for a nuanced approach that considers the specific needs and responses of each athlete.

Monitoring Athlete's Response to HIIT

Monitoring an athlete’s response to HIIT is crucial to optimizing training and avoiding overtraining or injury. Here are key tools and methods for monitoring, along with examples of different individual responses and signs indicating whether an athlete is a responder or non-responder.

Tools for Monitoring

1. Heart Rate Variability (HRV):

   • What It Measures: HRV measures the variation in time between consecutive heartbeats. It reflects the autonomic nervous system's regulation of the heart, indicating the balance between sympathetic (stress) and parasympathetic (recovery) activity.

   • How to Use: Athletes can use HRV monitors (e.g., apps like Elite HRV or devices like WHOOP, some training watch platforms - as an example my COROS does a good job and matches my WHOOP HRV metrics) to track daily HRV trends. A consistently high HRV indicates good recovery, while a decreasing trend may signal overtraining or inadequate recovery.

2. Perceived Exertion (RPE):

   • What It Measures: RPE is a subjective measure of exercise intensity based on how hard an athlete feels they are working. It is typically measured using the Borg Scale (6-20) or a simpler 1-10 scale.

   • How to Use: Athletes rate their exertion during and after HIIT sessions. Consistently high RPE scores, especially if not aligned with expected performance, can indicate fatigue or overtraining.

3. Performance Metrics:

   • What It Measures: Performance metrics include pace, power output, heart rate, and lactate levels during exercise. These metrics provide objective data on how an athlete is responding to training.

   • How to Use: Track performance over time, looking for improvements in speed, power, and endurance. Plateaus or declines may signal the need for training adjustments.

Examples of Individual Responses

1. Positive Responder:

   • Signs: Steady improvement in performance metrics (e.g., faster run times, higher power output), stable or increasing HRV, and moderate RPE scores relative to the intensity of workouts.

   • Example: An athlete whose 5K time decreases after a block of HIIT, while their HRV remains high and RPE stays within a manageable range, is likely a positive responder.

2. Non-Responder:

   • Signs: Little to no improvement in performance metrics despite consistent training, decreasing HRV, and high RPE scores.

   • Example: An athlete who sees no change in their pace or power output after several weeks of HIIT, experiences a drop in HRV, and consistently reports high exertion levels may be a non-responder.

3. Negative Responder:

   • Signs: Decline in performance metrics, significantly decreasing HRV, and very high RPE scores indicating excessive fatigue or stress.

   • Example: An athlete whose running pace slows down, HRV drops sharply, and who feels extremely fatigued during and after HIIT sessions might be a negative responder, possibly indicating overtraining.

Tell-Tale Signs of Responder or Non-Responder Status

1. Performance Trends:

   • Improving Performance: Indicates a positive response. Look for consistent improvements in times, power, or endurance.

   • Stable or Declining Performance: May indicate a non-responder or negative response. Investigate further to determine the cause.

2. HRV Patterns:

   • Stable or Increasing HRV: Suggests good recovery and adaptation to training.

   • Decreasing HRV: Indicates poor recovery, stress, or overtraining. Take action to address recovery and training load.

3. RPE Scores:

   • Moderate RPE: Indicates appropriate training load. The athlete feels challenged but not excessively fatigued.

   • High RPE: Especially if disproportionate to the intensity of the workout, suggests fatigue, inadequate recovery, or excessive training load.

4. Subjective Feelings and Feedback:

   • Positive Feedback: Athletes feel energized and motivated, indicating a good response to training.

   • Negative Feedback: Athletes feel chronically fatigued, unmotivated, or experience frequent minor illnesses or injuries, indicating a need to reassess the training approach.

Adjusting Training Based on Monitoring

• For Positive Responders: Maintain the current training load, incorporating progressive overload to continue improvements.

• For Non-Responders: Reassess the training program. Consider changing the intensity, duration, or type of HIIT sessions. Evaluate other factors such as nutrition, sleep, and overall recovery strategies.

• For Negative Responders: Reduce training load and prioritize recovery. Focus on low-intensity training, rest, and recovery modalities. Gradually reintroduce HIIT once recovery is achieved.

Conclusion

Monitoring tools like HRV, RPE, and performance metrics are essential for tailoring HIIT programs to individual athletes. Recognizing the signs of positive, non-, and negative responses helps optimize training, enhance performance, and prevent overtraining. Each athlete’s unique response underscores the importance of personalized training strategies in endurance sports.