There are so many interesting studies out there, I thought in this entry I'd just list some of the results and provide links.
Study 1: PNF stretching before weightlifting harms performance.
Study 2: Maximal strength training improves cycling economy in competitive cyclists.
Sixteen competitive road cyclists, male and female, participated. The test group performed "half-squats", 4 sets of 4 repetitions maximum, 3 times a week for 8 weeks as a supplement to their normal training. Although no changes in VO2 max or body weight occurred, test showed improvement in 1 rep max (naturally), cycling economy (4.8%), work efficiency (4.7%) and time to exhaustion at pre-intervention maximal aerobic power (17.2%). Conclusion: "Based on the results from the present study, we advise cyclists to include maximal strength training in their training programs."
Study 3: Weight training and on-the-bike strength training are beneficial at low cadences and in 30-minute endurance tests.
In this study, researchers set up a weight training group and compared them with an on-the-bike ("isokinetic") strength training group. They used 18 trained cyclists and had them do either weight training ro isokinetic training for 12 weeks. Both groups showed improvement in 30 minute performance and in max power at 40 rpms (around 15%). Surprisingly, isokinetic training did not improve max power at 120 rpms.
Study 4: In highly competitive endurance athletes, combined strength and endurance training yielded better results than endurance training alone.
In a study done on the Danish national cycling team, researchers found that heavy-resistance training resulted in a 7% increased mean Watt production in a 45-min time trial performance. The effect was purely physiological: increased proportion of type IIA fibers, les type IIb fibers, more muscle strength, more muscle force capacity, no size or mass increase, and no reduction in capillary density (that is, the same amount of oxygen could travel to muscles.
The authors of this study point out that previous studies which observed no benefit from weight training used short-term (9 weeks or less), low-resistance strength training programs rather than heavy-resistance, > 12-week programs.
One more interesting observation: cycling economy did not improve as a result of strength training in these elite cyclists. This seems to dispute the findings of study 2 (above) had found that weightlifting led to a 4.8% improvement in cycling efficiency. It's important to note that the increase in efficiency was seen in merely "competitive" cyclists; it's unlikely that lifting a few weights would improve the efficiency of members of the Danish national team: as the authors note, "cycling economy may already be optimized in top-level cyclists."
Check out the charts below. Notice how, in the top row, oxygen use decreases in the E+S Post (endurance and strength training) from before they began weight training, AND in comparison to the endurance (E) alone group. Notice, in the second row, how heart rate is lower, as well as lactate (row three).
In my next post, I'll try to use the results of these studies to come up with practical strength training advice: how much weight, how man reps, how many sets.