Strength Training for Runners/Triathletes 3

Strength training is a supplement to a runner’s roadwork because it strengthens muscles and joints, which can improve race times and decrease injury risk.

If you want to perform at your full potential, you need to take a comprehensive approach to your running by  targeting areas of fitness you may not normally pay attention to, such as  flexibility, balance, mobility, and strength in order to increase the amount of power you can produce in the muscles that propel  locomotion.

Multiple studies show that regular strength training can improve running economy-how efficiently the body uses oxygen-by as much as eight percent, translating into greater speed and more muscle endurance (8). Generally speaking, there are   two principal reasons your weekly training time should include a planned program of weight lifting.  First, lifting weights increases the strength of the muscles in the legs and upper body, which makes workloads of greater intensity more adaptable for  running  .  Second, weight lifting is not only good for your skeletal   muscles, but it also serves to strengthen all of the connective tissue in the joints.  Tendons (connect muscles to bones) and ligaments (connect bones to bones) are the connective tissues that play a crucial role in maintaining joint strength and integrity, and many of the lower body overuse injuries commonly suffered by runners could be significantly reduced if the tendons and ligaments were strengthened by minimizing connective tissue stress (bone, ligament, tendon, or cartilage) which plays a part in maintaining joint integrity and   making the entire support system more durable. Many runners don’t do strength training partly because they’d rather run if they have time for a workout. Sometimes running less and including strength training will benefit more than fitting in the miles. With age, strength training is even more important due to loss of lean muscle tissue which is vital to sustain a healthy body composition and prevent atrophy.

Endurance performance is a product of three physiologic variables: VO2MAX, Lactate threshold, and Running Economy (5). These three variables explain >70% of variation in endurance performance between individuals. Training can help improve VO2MAX, lactate threshold, and economy, which translates into greater fitness and improved performance. However, once aerobic capacity has been maximized, other variables, such as power, start to become increasingly vital to further improve performance(5).

Benefit # 1: Improving Running Economy

Interventions to improve RE are constantly sought after by athletes, coaches and sport scientists .  Resistance training, including training to develop strength and power, has been shown to improve running economy in many studies over the years. Strength training allows the muscles to utilize   more elastic energy and reduce the amount of energy wasted in braking forces(8). By improving running economy, a runner should be able to run faster over the same distance due to a decrease in oxygen consumption and thus would increase a runner’s time to exhaustion(7). Therefore, if every foot-strike you take in your race uses a lower percentage of your maximum force due to strength training, this allows one to operate at higher intensities and run at a higher velocity over a set duration .

Benefit # 2: Reducing Injuries Incurred: 

A stronger structure is a more resilient one. Running occurs one leg at a time and is basically hopping from foot to foot for miles and miles so it is important to build solid balance in your pelvis   to ensure balance with every step you take running. When your pelvis is stabilized, your entire body, gait and stride become more stable. The human body works as an integrated unit not one body part at a time and therefore should be trained as a unit(1). When you become fatigued, your form deteriorates (poor running economy) due to not only weary legs, but it is also due to exhausted arms ,back and abdominals. Having a strong torso helps hold your form together in the latter stages of a workout or a race. Strength training targets not only the muscles being worked but also the connective tissues surrounding the muscles and joints of the body which are often susceptible to injury over long distances and the cumulative fatigue due to runners ‘ high volume programs. Strengthening these tissues will enhance your chance of staying injury free in both the short term and over the course of your running career. Furthermore , since the incentive for the majority of runners is to train and race rather than winning races , introducing some basic strength work into their programs will help them to sustain and enjoy running into more senior years .

A study by Støren and colleagues (2008) investigated the influence of maximal strength training on running economy and time to exhaustion. Runners in this study completed four sets of four-repetition max of half-squats three times per week for eight weeks as a supplement to their normal training. The authors found that despite no changes in body weight or VO2MAX, the runners exhibited improved running economy and time to exhaustion (7). The results of this study suggest that strength training may improve endurance performance through improvements in neuromuscular characteristics rather than hypertrophy(7). Another variable that contributes to endurance performance is running speed at VO2MAX.  Although maximum speed is related to VO2MAX and economy, it also incorporates anaerobic capacity and neuromuscular characteristics. When athletes are matched for aerobic capacity (VO2MAX), anaerobic power and neuromuscular characteristics contribute to endurance performance. Thus a highly trained athlete can further improve performance by maximizing strength and power (7).

A recent review by Rønnestad & Mujika (2013), found that concurrent endurance and heavy strength training increases speed at VO2MAX  (Vmax) or time to exhaustion at Vmax (6). In this review, the authors identify muscle fiber recruitment pattern as a potential mechanism for improved performance after combined strength and endurance training. Strength training increases the maximal strength of type I (slow twitch) muscle fibers delaying their time to fatigue, which in turn delays the activation of less economical type II fibers(6).

Another potential mechanism for improved performance is the conversion of type IIX (fast twitch) to type IIA (fatigue-resistant fast twitch) fibers. In a recent study examining a 16-week concurrent strength and endurance training on cyclists, the authors found an increase in type IIA fatigue-resistant fibers (4). A shift from type IIX to type IIA fibers improves endurance performance because type IIA fibers exhibit a high power output yet are more fatigue resistant than type IIX fibers . This leads to greater muscular efficiency and delayed fatigue in endurance performance (4).

Improved musculo-tendon  stiffness has also been identified as potential mechanism for improved endurance performance in response to strength training(11). In a study by Foure and colleagues (2011), subjects participated in a 14-week plyometric training program to assess the impact on stiffness and jumping performance. The authors found an increase in joint stiffness after the training program, leading to enhanced elastic energy storage (11). In terms of endurance performance, explosive strength training increases lower body stiffness leading to improved utilization of the elastic energy and reducing the energy cost of running. Taken together, these studies suggest that maximal or explosive strength training is most beneficial for runners. The addition of strength training to an endurance training program can further increase running economy and subsequent  performance(11). This is especially true when all other physiological variables have been maximized through training. Despite the popularity of lower weight/high rep strength training among runners, the evidence points to greater performance benefits from maximal and explosive strength training(11).

As for strength training making you bigger, muscle bound and slower, it is just not going to happen on a high volume endurance based program.  It takes a special genetic make – up, lots of work, and a considerably different muscle structure than most long distance runners have to “get big”. Long distance runners have primarily aerobic slow twitch fibers that do not enlarge as do the Fast Twitch muscles found in most body builders and in sprinters(8). Sprinters with their high concentration of anaerobic capable FT (Fast Twitch) fibers can show more muscle mass gain with strength training. This training is a requirement to compete at a high level.

Nevertheless, even in endurance sports, as a result of strength training, ground contact time is reduced because of rapid force production  due to increase strength and power which ensures a higher running speed. .Running is made possible by the body’s structural and neuromuscular adaptations of the shoulders and hips; we run shoulder to opposite hip(3). Running speed = stride length x stride frequency. Stride length is a function of strength, power and flexibility. Collectively, stability and balance are the guiding system of the power needed for a longer stride length. Mobility and Stability must coexist to create efficient movement in the body.(2)  The Core controls the rotational mechanics between the upper and lower extremities (running efficiency and stride frequency) and the force production of the lower body (stride length)(2). Thus, regardless of the opposing variations of strength and endurance training   recreational and elite endurance athletes may perform both types of training concurrently to optimize endurance performance. Many different models exist for periodization of resistance training, particularly when it is performed concurrently with endurance exercise.

Strength exercises for runners include power cleans, kettle bell swings, TRX suspension training and lifting heavy weights with low reps as well as  a lot of explosive exercises or plyometrics, such as box jumps(10).

Plyometrics improve running performance by enhancing leg stiffness during running(11). The legs function as springs when you run. Each time a foot lands, the body sends impact forces into the ground; these forces then rebound back into the foot, propelling forward motion. About half of the energy required for running comes to us “free” from these physics. However, not all of the energy that enters the ground comes back into the foot and is used for propulsion. A certain amount dissipates and therefore the relative stiffness of the legs is one major factor that  determine  how much of the available free energy is captured and used. A runner who has   tight joints and is able to tense the right muscles to the right degree at the right time creates a stiffer spring that captures more energy. Plyometrics enhances this ability.  These types of exercises lead to neuromuscular adaptations within the muscles that in turn, improve running economy, and eventually performance(11).

Core and upper body are also important for endurance running. Core means more than just abdominal strength however. .  There are approximately 29 pairs of muscles that support the lumbo-pelvic-hip complex and the spine.  These muscles provide support to the spine and pelvic area during functional kinetic chain  movements(3) . The   “core” has been described as a box with the abdominals in the front, paraspinals  and gluteals  in the back, the diaphragm as the roof, and the pelvic floor and hip girdle musculature as the bottom(3). Particular attention has been paid to the core because it serves as a muscular corset   that works as a unit to stabilize the body and spine, with and without limb movement.  In short, the core serves as the center of the functional kinetic chain(3).

For the best results, strength training should be included year round. Endurance runners often include either very little or no resistance training in their exercise programs, especially when increases in running volume occur, which makes the periodization of concurrent strength and endurance training in endurance runners very different from that of strength and power athletes Strength training should follow the same type of periodization as a normal training plan. In the off-season the focus should be on more weight and lower reps for building strength and focus on addressing any weaknesses. As a runner enters the pre-season, the focus should shift for more explosive body weight exercises, such as box jumps, medicine ball exercises, pushups, pull-ups, and abdominal exercises.

In summary, strength training is important—both for health and performance. The type of strength training you need depends on your goals as an athlete. For the recreational runner interested in general health and fitness, focusing on core and/or muscular endurance is sufficient. For a runner looking to enhance endurance performance, maximal strength training is most advantageous. The best way to improve strength is to be consistent with a routine. Incorporate single leg training (e.g. one leg squat) and train primarily in a standing position. Train in diagonal or transverse patterns – opposite hip to opposite shoulder – just like we run(2). Emphasize “pulling power for improved stride length(2) . Focus on power and initiating and controlling running from the core of the body downward. . Change the exercises you are using each month to keep mentally stimulated and to ensure that strength gains continue (runners can quickly plateau if they do the same exercises month after month).

References

1. Clark, M.A. & Lucett, S.C. (2011). NASM Essentials of Corrective Exercise Training. Lippincott,   Williams & Wilkens. Baltimore, MD, 8-81.

2. Cook, Gray .Athletic Body In Balance .Human Kinetics. 2003.

3 .Neumann , Donald A. Kinesiology of the Musculoskeletal System- Foundations for Rehabilitation: 2ndEdition. St. Louis: Mosby Inc, 2009.

4.Aagaard P, Anderson JL, Bennekou M, Larsson B, Olesen JL, Crameri R, Magnusson SP, Kjaer M. Effects of resistance training on endurance capacity and muscle fiber composition in young top-level cyclists. Scand J Med Sci Sports 2011;21:e298-e307.

5 .Barnes KR, McGuigan MR, Kilding AE. Lower Body Determinants of Running Economy in Male and Female Distance Runners. J Strength Cond Res. 2013 Oct 11.

6. Rønnestad BR, Mujika I. Optimizing strength training for running and cycling endurance performance: A review. Scand J Med Sci Sports. 2013 Aug 5. doi: 10.1111/sms.12104.

7.Støren Ø, Helgerud J, Støa EA, Hoff J. Maximal strength training improves running economy in distance runners. Med Sci Sports Exerc. 2008; 40(6):1087-92.Sports Medicine June 2004, Volume 34, Issue 7, pp 465-485

8. R. S. Taipale 1 , J. Mikkola 2 , A. Nummela 2 , V. Vesterinen 2 , B. Capostagno 3 , S. Walker 1 , D. Gitonga 1 , W. J. Kraemer 4 , K. Häkkinen. Strength Training in Endurance Runners . Int J Sports med…, 2010

9. Mikkola, J., Vesterinen, V., Taipale, R., Capostagno, B., Häkkinen, K., & Nummela, A., Effect of resistance training regimens on treadmill running and neuromuscular performance in recreational endurance runners. Journal of Sports Sciences, 2011  29(13), 1359-1371.

10 .Taipale, Ritva S.; Mikkola, Jussi; Salo, Tiina . Mixed Maximal and Explosive Strength Training in Recreational Endurance Runner.Journal of Strength & Conditioning Research. 2014 28(3):689-699.

11. Fouré A, Nordez A, Guette M, Cornu C. Effects of plyometric training on passive stiffness of gastrocnemii and the musculo-articular complex of the ankle joint. Scand J Med Sci Sports. 2011 19: 811–818.

Robert Haviland MS,P.T.A, CSCS,CES