Attention all runners, if you want to improve your running times, get into the weight room! If you don't want to listen to me, at least take George Perry's advice. George is the director and running coach for the Austin Track Club and this week, he'll not only explain why strength training is important, but he'll also show us a sample workout that he uses with his runners. Enjoy... Middle-distance running events range from 600m to 3000m. The quintessential - and most commonly competed - mid-distance events are the 800m and 1500m /1 mile. Mid-distance events last from about 1-10 minutes, from male 600m runners to female 3000m steeple-chasers. The metabolic requirements of racing at these distances present unique demands to running coaches and strength and conditioning coaches alike.
Pietro di Prampero understood the human machine by applying basic principles of mechanical engineering to human locomotion. The equations underlying all of his work are:
v = E/C,
E = Al + L + MAP(F)
v = speed (m/s)
E = the metabolic power above resting (in W/kg)
C = the energy cost of the activity (J/kg/m).
Al = anaerobic alactic power output
L = anaerobic lactic power output
MAP = maximal aerobic power (VO2max)
F = fractional utilization of VO2max, a function of the duration of the activity
Running economy is the oxygen consumption necessary to run at a given submaximal pace, in milliliters of oxygen per kilogram per minute. The energy cost of running relates to running economy via the standard approximation that 1 ml of O2 consumed produces 20.9 J. For two runners with the same maximal aerobic power (VO2max), the more economical runner will run the same pace at a lower percentage of VO2 max. This theoretically increases the time she can maintain that pace, and reduces the effort level for any given pace. Because the cost of running is independent of speed, maximum running speed (v max) depends on the maximum metabolic power (Emax) that the athlete can generate.
Maximal activities lasting between 1-10 minutes, such as middle-distance running, rely on a combination of anaerobic and aerobic sources that are not encountered in sprints or long-endurance events (Figure 1). Figure 2 shows that improvements in both anaerobic and aerobic energy systems have a much greater impact on middle-distance performances than races 5000m or longer.
Coaches and athletes in middle-distances need to attack all determinants of speed in di Prampero’s equation: increasing aerobic and anaerobic power output (E) and decreasing the cost of running (C). Of these factors, strength training has the highest impact on the cost of running and the amount of power generated by anaerobic lactic systems.
Exercise physiologist (and collegiate track athlete) George Brooks was the first to fully describe how athletes use lactate - once widely regarded as a performance-degrading waste product of metabolism - as a critical fuel source. Brooks’ experiments demonstrate that “lactate is the link between oxidative and glycolytic, or anaerobic, metabolism.” Figure 1 (above) highlights that middle-distance athletes make their living in the zone between oxidative and glycolytic metabolism. The ability to rapidly produce a large amount of lactate, clear it out of the muscles and reuse it as fuel is of critical importance to the middle-distance runner.
Table 1 and 2 show lactate production and tolerance workouts on the track and in the weight room for a male 800m runner.
During the first two-thirds of a season, we perform these (or similar) track workouts every 10-14 days. Between these sessions, we incorporate strength training that induces similar lactate kinetics as a complement to the track workouts. While the levels of lactate produced with strength training are less than those attained by running, similar metabolic pathways are engaged with reduced stresses on the athlete. This enables us to keep the body’s adaptive processes more fully engaged for a longer period of time, without overloading the athlete.
Table 1. Lactate Production
Table 2. Lactate Tolerance
Improving running economy is one of the most widely accepted benefits of strength training for runners. Numerous mechanisms have been put forth for how strength training makes runners more economical: increased rate of forced development, more efficient muscle fiber recruitment patterns, improved musculo-tendinous stiffness and altered fiber-type distribution patterns are a few of the more commonly cited. Likewise, researchers have demonstrated that various strength training modalities can improve running economy.
Among well-trained runners, neuromuscular factors underlie most improvements in peak speed and running economy. Combining near-maximal strength training with plyometrics allows us to induce a combined effect of anaerobic power production and neuromuscular activation. These adaptations come about via post-activation potentiation, an improved stretch-shortening cycle and maximum power generation. Table 3 shows one workout that we perform every 7-10 days. Over the course of the season we raise the height of the box jumps to ensure an equally challenging stimulus for the athlete, consistent with research demonstrating increases in countermovement jump height with improved running economy.
Table 4. Austin Track Club Sample Workout
Future Directions: Velocity- and Mechanical Output-Based Training
The mechanisms by which strength-training induces lactate accumulation differ in part from running. The increased intramuscular and capillary pressure during resistance training likely induces a partial blockade in the capillaries. The working muscle, therefore, transitions to anaerobic processes because of a “forced” condition, rather than as a result of power demands. Monitoring an athlete’s lactate accumulation while manipulating both the load and movement velocity can allow us to better simulate the conditions that lead to lactate production in a runner, thereby improving the specificity of training. We can also look for load-velocity relationships that produce greater amounts of lactate to further improve the athlete’s lactate production and set the conditions for more effective lactate tolerance and lactate clearance strength training exercises.
By rearranging di Prampero’s long-form equation, plugging in the athlete’s goal race pace, VO2max and energy cost of running (readily measurable at a sports science lab) we can determine the anaerobic power he will need to produce to hit his goal time. With PUSH providing measures of mechanical output, researchers and practitioners in middle-distance running can explore event-specific load-based training. In the same way that we currently compute workout intensities and volumes as percentages of recent performances, goal times and event distance, PUSH's output will allow us to prepare strength training systems built around the metabolic-mechanical linkages that drive the human machine. Knowing the power demands of an athlete’s goal will allow us to approach strength training for event-specific power production, rather than general measures of strength and speed. Speed is “merely” the manifestation of metabolic-mechanical output. By targeting the upstream processes with the specificity and rigor that we target the final output, we will be able to innovate new training methods that will give our athletes the competitive edge.
References for Suggested Reading
Buitrago et al, 2013. Mechanical load and physiological responses of four different resistance training methods in bench press exercise. Journal of Sterngth and Conditioning Research. PUBMED
De Souza et al, 2012. Acute Cardiorespiratory and metabolic responses durng resistance exercise in the lactate threshold intensity. International Journal of Sports Medicine. PUBMED
Di Prampero et al, 1993. Energetics of best performances in middle-distance running. Journal of Applied Physiology. PUBMED
Ferretti et al, 2011. An analysis of performance in human locomotion. European Journal of Applied Physiology. PUBMED
Gladden 2004. Lactate Metabolism: a new paradigm for the third millennium. Journal of Physiology. PUBMED
Guglielmo et al, 2009. Effects of Strength Training on Running Economy. International Journal of Sports Medicine. PUBMED
Sedano et al, 2013. Concurrent training in elite male runners: The influence of strength versus muscular endurance training on performance outcomes. Journal of Strength and Conditioning Research. PUBMED