An Analysis of Hadd’s Approach to Distance Training

If you are a frequent visitor to running related web forums, you may have been exposed to a training method entitled “Hadd’s Approach to Distance Training”.  As I understand the story behind this training method, it was written by a fellow named John Hadd who originally posted it to the LetsRun forum.  It sparked considerable interest and a copy was subsequently saved for reference for those who might be interested.

With the publishing of the article a number of runners have adopted Hadd’s training approach and some, though not all, have reported positive results.  Their results in turn have sparked additional interest in Hadd’s methods by other runners.  In light of the increasing interest in his approach and the reported positive results of some who have followed it, I thought it appropriate to analyze Hadd’s training method.  The purpose of my analysis was to gain an understanding of Hadd’s methods and to examine the logic of his training prescription.  Is there something unique about Hadd’s training or testing program or is it a variation of accepted training methods?  Let’s find out.


Hadd begins with the presentation of some general ideas in his paper.  He starts by explaining that 1) there is a relationship between performance at different running distances and 2) that for any particular runner a non-relationship between performances at varying running distances is caused by a low lactate threshold.  Hadd then explains that a low lactate threshold is due to insufficient mitochondrial development within the working muscles.  Hadd’s goal is to improve lactate threshold by increasing mitochondrial and capillary density within the working muscles.

Hadd explains that the two primary reasons a runner may have too few mitochondria are insufficient weekly training mileage and/or mileage being run too fast.  The goal of Hadd’s training is to increase mitochondrial and capillary density thereby increasing lactate threshold.  He accomplishes this by having the runner increase weekly training mileage to as much as 116 miles per week (mpw) and carefully controlling the pace of every training session using a heart rate monitor.  To illustrate his training method for improving lactate threshold Hadd uses an example of a runner he coached named Joe.

Here are Joe’s vitals:  5 years prior to the writing of this paper, Joe, at age 30, ran two 2:27 marathons.  In the interval, Joe has gained weight, dropped hard training, and now runs just 20 miles per week, all at a slow pace.

Hadd has Joe begin by building to 50 miles per week of running, all via easy paced runs.

Once Joe reaches 50 mpw, Hadd has Joe perform a fitness test that measures Joe’s running pace at various heart rates.  Hadd also has Joe perform a test to discover his HRmax, which is 193.

With the data from Joe’s fitness test and HRmax test, Hadd devises a 20 week training schedule for Joe.  This schedule has Joe running 7 days per week and increases Joe’s weekly mileage from 50 mpw to a maximum of 116 mpw.  Hadd also carefully describes the intensity of each run – with intensity being prescribed by %HRmax.  About every six weeks Hadd has Joe repeat the fitness test to measure improvements.

Setting aside Hadd’s extensive commentary about the underlying physiology, the goals of the training and Joe’s results throughout the twenty week training period, following are the basic details of Joe’s workouts:

Sample training week, 60 miles per week:

Mon60 min easy145 HR
Tue75 min easy160 HR
Wed45 min easy145 HR
Thu60 min easy150 HR
Fri75 min easy160 HR
Sat45 min easy150 HR
Sun90 min easy155 HR

Joe basically conducts 3 workouts at 155 – 160 HR, 2 workouts at 150 HR, and 2 workouts at 145 HR each week.  To increase his mileage to as high as 116 mpw, Hadd has Joe generally increase the distance of all his runs.  As Joe’s fitness improves throughout he is able to run at increasingly faster paces for the same prescribed training heart rate.

Sample training week, approx. 80+ mpw

Mon60 min easy140 – 145 HR or lower
Tue90 min w/ 70 @ 160 HR 
Wed75 min easy140 – 150 HR or lower
Thu75 min easy150 – 155 HR
Fri90 min w/ 70 @ 160 HR 
Sat75 min easy140 – 155 Hr or lower
Sun3 hrs easy145 – 155 HR (w/60@160 HR

Using 155 HR as the dividing line between faster and slower paced training, here is a breakdown of the faster paced efforts Joe makes for the 20 week training period:

Weeks 1-7, Joe does not run at a pace higher than 160 HR.  He conducts 2-3 workouts at 155 – 160 HR each week.

Weeks 8 – 12:  Intervals of 200m x 25 repetitions @ 5k pace replace one of the 160 HR workouts. (5k race pace generally corresponds to VO2max pace or 95% HRmax)

Week 13:  2 workouts of 165–170 HR, replacing two 160 HR workouts.

Week 14:  1 workout at 165 – 170 HR and a 5k race @ 186 HRaverage

Week 15:  1 session at 169 HR and one session of 3 x 15 min @ 170 HR

Week 19:  Half marathon @ 181 HRaverage

At this point in the article, Hadd ends his discussion of the specifics of Joe’s training.  Hadd explains how other runners can adopt his training method, providing guidelines for runners with a different HRmax than Joe’s 193.  Hadd then closes with some guidance as to how to train upon completion of the 20 week program and how to know when to add in faster paced training.


For sake of discussion, we will assume that Joe is a real person and the data provided on him is accurate.  During the 20 week training period, Joe’s performance steadily improves.  Hadd provides significant physiological explanations for Joe’s improvements based on improved lactate threshold.  Without commenting on the underlying physiology presented by Hadd, let us examine Joe’s training to see what we can learn.  We know that Joe’s maximum heart rate is 193.  An analysis of Joe’s training heart rates reveals the following:193 = HRmax186 = 95% of HRmax181 = 94%170 = 88%165 = 85%160 = 83%155 = 80%150 = 78%145 = 75%

What is the significance of the above training heart rates?

Joe’s training heart rates above 150 are significant because according to many experts he is training at a sufficient level of intensity to cause a significant training adaptation.  In their book Road Racing for Serious Runners, Pfitzinger and Douglas note that lactate threshold training is conducted at 80% – 90% of HRmax.  In their follow up book, Advanced Marathoning, Pfitzinger and Douglas again note that lactate threshold is 80% – 90% of HRmax.  Rob Sleamaker, in his book, Serious Training for Serious Athletes, uses the term Level 4, corresponding to 81% – 90% HRmax.  Sally Edwards and Ed Burke use the term Zone 4 which is conducted at 80% – 90% of HRmax.  In each case, the authors explain the importance of training at this particular intensity and note that significant improvements are expected to occur from training conducted at this intensity.

In Joe’s case, he ran 2 or more workouts per week at 80% HRmax or above.  In light of the fact that workouts of this intensity are easily sufficient to cause an improvement in performance, it’s no surprise that Joe experienced the changes he did.  He was simply training at an intensity that is widely known and accepted to cause performance improvements.  As his fitness improved, Joe increased his training pace to ensure his intensity level remained at 80% or above resulting in on-going improvements during the entire 20 week training program.

The second major thing Joe did was to increase his weekly training mileage from 50 mpw to as high as 116 mpw, more than doubling his training volume.  While I am not a fan of high weekly mileage, I do recognize that volume of training is one of the elements of training and exerts an influence on performance.  The more than doubling of weekly training mileage could improve performance if the runner can continue to recover sufficiently.  Proponents of high weekly mileage could easily point to Joe’s doubling of weekly mileage as the cause of Joe’s improvements.

Additionally, in order to increase his overall training mileage, the length of all of Joe’s run were increased, including the length of his higher intensity workouts.  For example, in the 60 mpw training schedule Joe ran for 75 minutes at 83% HRmax.  In the 80 mpw schedule, Joe increased this run to 90 minutes at 83% HRmax.  So, while the intensity of effort (83% HRmax) was retained, the overall intensity of the workout was increased by running for a longer period of time.


Without analyzing Hadd’s physiological explanation for his methods, a review of his approach to training reveals that he prescribes two major things: 1) 2 – 3 workouts per week at intensity levels well known to cause significant performance improvements and 2) large increases in weekly mileage.  Neither of these are novel approaches to training – indeed they are both integral parts of conventional training wisdom.  The one noticeable difference in Hadd’s program is the unique 2400m fitness test he has the runner conduct approximately every 6 weeks to measure improvements in fitness.  This test provides valuable feedback to the runner as to fitness improvements, but the test in and of itself would not be expected to influence performance in any way.