Training the Thresholds

Posted by Scott Christensen

The summer months are an excellent time to review the scientific basics of the aerobic energy system training and reflect back on how your athletes performed last spring following their particular training program.  From the performance data sets of your athletes you can diagnostically check to see if you had them properly prepared for the rigor of their particular endurance events.  Remember all middle-distance events have a significant contribution of aerobically produced energy that accompanies what is supplied anaerobically – so you must begin training the thresholds at the start of the season. If fully utilized the aerobic energy system supplies about 50% of the energy needed to perform the 800 meters and about 80% in the 1600 meters.  The more robust and developed the aerobic system is at race pace leads to performances that are able to fully reach their race percentage profile.


Aerobic training modalities in middle-distance events are based upon the athlete’s on-going VO2 max development and the running pace derived from that development.  From this pace, which is called vVO2 max pace, you can fractionize the value to determine and train that athlete at both their aerobic and lactate thresholds.  vVO2 max pace can be determined on a laboratory treadmill, or by using the Astrand field test where the protocol is the amount of time it takes the athlete to run two miles to exhaustion and then dividing that value in half to get the per mile velocity of  current date VO2 max. Once that numerical value is known for each athlete, training can be set up exactly at that pace to try to push vVO2 max even faster.    .

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The fractional use of vVO2 max determines the pace of both long run and tempo run workouts by synchronizing this pace to the aerobic and lactate thresholds respectively.  The robust development of the aerobic energy is tied to once per week workouts at both the aerobic threshold pace and lactate threshold pace.  Work done in both the physiology lab and in the field on world class distance runners has determined the aerobic threshold pace of an individual to be 70% of their vVO2 max pace and the lactate threshold pace to be 85% of their vVO2 max pace.  As the VO2 max system improves throughout the season, so will the derived pace.  Since the fractional use of VO2 max is tied to this improving value, then the long run and tempo run paces will increase as well.  Training at the thresholds begins the first week of the season and extends to the last week of the season and is the basis for the bulk of the aerobic training of middle-distance runners.


During any 12 day middle-distance training microcycle during the season the athlete should do one dedicated VO2 max workout at vVO2 max pace, one workout near the lactate threshold pace, and at least one long run and a couple of other shorter recovery runs at the aerobic threshold pace.  All of these paces are date paced and tied to the athlete’s fitness at that particular time of the training season.  Since middle-distance training is also multi-tiered those workout paces will gradually improve as the VO2 max fitness of the athlete improves.


An array of workouts can be placed into an athlete’s annual training plan that addresses these training paces.  The long run should be 20% of the weekly mileage of the athlete and completed in one continuous run.  By running at the aerobic threshold for this distance, the volume, not the intensity, becomes the primary training stimulus.  While running at the aerobic threshold pace the primary metabolic fuel used is free fatty acid processed through the mitochondria with oxygen present.  Carbohydrate fuel is thus spared for a harder anaerobic workout the next training day.  There are no metabolic byproducts left behind to retard recovery from the long run.  Fatigue from the long run is mainly in the central nervous system with very little residual stress on the aerobic energy system.


A training run done at the lactate threshold for a middle-distance runner should be 4-5 miles in length at lactate threshold pace.  Remember, this pace is determined by 85% of vVO2 max pace.  This workout type primarily uses carbohydrate as the metabolic fuel.  Keep in mind, because there are less carbohydrate molecules than fat molecules stored in the body it is more stressful to run at the lactate threshold than at the aerobic threshold.  There is also some lactate produced while running that causes slight cell membrane damage that may cause soreness the next day and necessitates a 48 hour recovery from the workout.


As you look back at your middle-distance workouts, did you do enough of this type of work to build a robust aerobic energy system in your athletes?  All three of these workout types must be done about once per week during the season.  Scientific research has suggested that approximately 80% of an individual’s aerobic power is genetically determined.  However maximal aerobic power can be enhanced through progressive endurance training.  On average, VO2 max can be increased by 15-20% or more in untrained individuals depending on the initial level of fitness.  In contrast, it is unlikely for an elite level athlete to realize an increase in VO2 max of greater than 3-5% due to the relatively high level of conditioning already attained by the elite middle-distance athlete.  Training at the thresholds is your best means for attaining any level of aerobic development in the shortest amount of time.

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Scott Christensen - Scott Christensen’s teams have been ranked in the national top 10 eight times. He won the 1997 High School National Championship and his squads have captured multiple Minnesota State Championships. Scott has coached 13 Minnesota State Championship-winning teams and 27 individual Minnesota State Champions. He was the USTFCCCA Endurance Specialist School junior team leader for the World Cross Country Team in 2003 and the senior team leader in 2008. Scott is a 14-year USATF Level II endurance lead instructor.

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