Over the last 30 years, both male and female Ironman triathlon times have improved modestly. Performance differences between competing male and female athletes within the individual events of running and swimming have decreased slightly, narrowing the gap. However, as we draw our attention to the cycling event alone, we are seeing this difference in performance slowly increase (Lepers 2008). Women consistently generate lower power output on the bike (38 percent less) and trailed men by 11 percent in cycling time performance in the 2007 World Ironman (Lepers 2008). Males also have a higher absolute power output than their female counterparts when it comes to sprint cycling (Tanaka et al. 1993), even when the data is normalized to total body muscle mass (Bar-Or 1987; Green 1995). This is also the case during longer road cycling with professional male riders averaging around 466 W or 6.7 W/kg (Lucia et al. 1998) and competitive female cyclists averaging around 259 W or 4.26 W/kg (Martin et al. 2001).
However, when power output during sprint cycling is normalized to lower body muscle mass, females are much closer to males (Tanaka et al. 1993). This suggests that one of the main reasons for the increased gender difference in cycling may be total body muscle mass and to a lesser extent, lower extremity muscle mass where localized muscular fatigue is the main determinant of success. Despite the fact that power output normalized to lower body muscle mass is closing between genders, only the top female riders are approaching average male power output values. Males still seem to have a more homogeneous population of riders (the difference between top 10 male riders is much smaller than top 10 female riders) (Perez-Gomez et al. 2008), suggesting that the majority of females are not reaching their lower body muscle mass and thus, power generation potential.
There are two main factors that determine power output in skeletal muscle:
- Rate of force development
- Maximal force per cross-sectional area (Malisoux et al. 2006)
According to Stone’s research, women in general have a smaller cross-sectional area of Type IIa and Type IIx muscle fibres than men, and that this may limit power output (2006). This combined with the notion that females may have more compliant (less stiff) muscles than males means that females may have a harder time creating and maintaining peak tension. Because of this, women may also take longer to reach their peak power output and have a greater decline in power output after peak power is reached (Billat et al. 2003).
So what variables have the most influence on rate of force development and maximum force per cross-sectional muscle area of Type II muscles fibers, and as a result... power output? Well, one is genetics and the other is methodology of training. Since none of us seem to have the power (no pun intended) to change genetics, let’s discuss methodology of training.
The three main factors influencing endurance performance are:
- Maximal aerobic power (VO2 max)
- Lactate threshold
- Exercise economy
At the elite level, margin of difference in VO2max (maximal oxygen consumption) and lactate threshold (ability to work at a higher percentage of maximum without exceeding this threshold) between the top cyclists is quite minimal. The bottom line is that female riders are not strong enough. Getting cyclists stronger will ultimately make them more powerful and may even increase their endurance capacity (Anderson 1982). When strength is increased, rate of force development also increases, which improves exercise economy (Osteras et al. 2002). Economy of movement is the amount of muscle activation or energy expenditure at a given load. With strength training, the body reduces the amount of total muscle activation at a given load. This conserves energy, allowing fewer motor units to do the job of driving powerful muscle actions, thus creating more of a reserve for additional work. Economy may make up for a relatively low VO2 max in cyclists and is the variable that is most easily influenced with correct strength training methods (Lucia et al. 2002; Hoff 2002). Paavolainen et al prescribed a wide spectrum of plyometrics and explosive strength training drills and showed enhanced power production as well as improved oxygen consumption in their athletes, albeit they were 5km runners (1999). We see this when comparing amateur and elite cyclists; similar VO2 max levels are seen between the two groups, with cycling economy and gross mechanical efficiency being the difference in performance (Lucia et al. 2002). By increasing lower body strength/power and improving cycling economy via proper biomechanics, technique and posture, we can improve cycling power output and possibly help the girls catch the boys.
But with the same training methods available to both males and females, why are we still faced with this gender difference in cycling performance? It simply boils down to what these athletes are doing in the off season. Female and male athletes respond exactly the same way to strength training protocols and periodization schemes, which means adaptation and responsiveness to a training stimulus is not gender dependent. And with the right choice of exercises, in the correct order, with lengthy rest intervals, strength and power gains are maximized, and hypertrophy is minimized. Female triathletes and cyclists need to get in the weightroom and get stronger and stop fearing that it will add unnecessary bulk to their frames. And the main objective of strength coaches must be to improve the athlete’s rate of force development and maximal force per cross-sectional area.
How do we do this? First we begin with the big picture. During the strength phase of a triathlete or cyclist, the load should be increased in steps of three, not four or five, followed by an unloading step. This loading and unloading should mirror the athlete’s energy system work. There should also be approximately nine to 15 weeks of maximum strength training in the training plan. The duration of this phase is also dependent on whether the athlete has to follow a single or double peak annual periodization plan. Strength training should make up approximately 10 to 15 percent of total training hours. It is recommended that an endurance athlete focus on maximal strength development two times per week to allow for recovery and restoration of muscle glycogen stores.
Next, the athlete enters a power phase where the strength coach can prescribe powerful concentric movements and/or plyometric exercises. It may either precede or coincide with race-pace energy system training. This phase is also relatively short as compared to the maximum strength phase, about four to six weeks in duration. Because the athlete is getting closer to competition, he/she may only train using power methods once per week, depending on the volume and intensity of the energy system work outside of the gym. It should also be noted that the endurance training during this phase may be very intense. If this is the case, special attention must be paid to the microcycle of training so there is adequate time for restoration on energy stores. If the athlete has the physical and adaptive capacity to train twice per week, the joints should be unloaded on the second training session. Power training during this phase should make up approximately five to 10 percent of total training hours.
As mentioned previously, one of the main reasons for the increased gender difference in cycling performance may be lower extremity muscle mass, and thus, the majority of females are not reaching their power generation potential. Consistent and intense strength and power training can be an effective component of the female cyclist’s off season plan when careful consideration is made to timing sessions, loading and unloading weeks as well as optimizing recovery.
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