Two different studies - LSD vs HIT

Both of these highlite the importance of keeping HIT (High Intensity) down and LSD (Long Slow Distance) up.


The easier and shorter read from Dr. Stephen Cheung, Ph.D. http://www.pezcyclingnews.com/default.asp?pg=fullstory&id=9472

•Total training time was strongly correlated with FTP and VO2max. This observation strongly supports the above correlation with overall rider ranking.

• The amount of time spent in “aerobic endurance” workouts and at the Zone 2 (Endurance) power zones also strongly correlated with both FTP and VO2max. This is a very interesting finding and runs counter to most our pre-conceptions that better fitness comes through better/harder/more intervals. Rather, this points to the importance of developing that big “aerobic engine” as the foundation for better fitness. Indeed, many of us, despite our limited training time, probably do as much higher intensity work as elite riders with double our training volume. So if you can arrange to have a week or two of increased training volume, it may be best to focus on endurance efforts rather than more intervals or high-intensity work.

• The above finding is about total time in aerobic endurance work. However, the overall distribution of training time at different zones were similar across all 11 subjects, averaging ~73 in Zones 1-2, 22% in Zones 3-4, and 5% in Zones 5-7. Note again the preponderance of relatively “easy” endurance work even in elite/world class cyclists. This suggests that the mix of training is about the same across these elite athletes, and again that “quality equals quantity” even at these elite levels.

• FTP was most strongly correlated with total training time spent doing “strength” workouts, which consisted of low cadence (40-60 rpm) high gear efforts for 2-20 min. 
• The amount of time spent in “aerobic endurance” workouts and at the Zone 2 (Endurance) power zones also strongly correlated with both FTP and VO2max. This is a very interesting finding and runs counter to most our pre-conceptions that better fitness comes through better/harder/more intervals. Rather, this points to the importance of developing that big “aerobic engine” as the foundation for better fitness. Indeed, many of us, despite our limited training time, probably do as much higher intensity work as elite riders with double our training volume. So if you can arrange to have a week or two of increased training volume, it may be best to focus on endurance efforts rather than more intervals or high-intensity work.
• The above finding is about total time in aerobic endurance work. However, the overall distribution of training time at different zones were similar across all 11 subjects, averaging ~73 in Zones 1-2, 22% in Zones 3-4, and 5% in Zones 5-7. Note again the preponderance of relatively “easy” endurance work even in elite/world class cyclists. This suggests that the mix of training is about the same across these elite athletes, and again that “quality equals quantity” even at these elite levels.
• FTP was most strongly correlated with total training time spent doing “strength” workouts, which consisted of low cadence (40-60 rpm) high gear efforts for 2-20 min. 

And the longer and more in depth peer reviewed paper from Stephen Seiler and Espen Tønnessen  http://www.sportsci.org/2009/ss.htm

Here are some conclusions that seem warranted by the available data and experience from observations of elite performers:
•       There is reasonable evidence that an ~80:20 ratio of low to high intensity training (HIT) gives excellent long-term results among endurance athletes training daily.
•       Low intensity (typically below 2 mM blood lactate), longer duration training is effective in stimulating physiological adaptations and should not be viewed as wasted training time.
•       Over a broad range, increases in total training volume correlate well with improvements in physiological variables and performance.
•       HIT should be a part of the training program of all exercisers and endurance athletes. However, about two training sessions per week using this modality seems to be sufficient for achieving performance gains without inducing excessive stress.
•       The effects of HIT on physiology and performance are fairly rapid, but rapid plateau effects are seen as well.  To avoid premature stagnation and ensure long-term development, training volume should increase systematically as well.
•       When already well-trained athletes markedly intensify training with more HITover 12 to ~45 wk, the impact is equivocal.
•       In athletes with an established endurance base and tolerance for relatively high training loads, intensification of training may yield small performance gains at acceptable risk.
•       An established endurance base built from reasonably high volumes of training may be an important precondition for tolerating and responding well to a substantial increase in training intensity over the short term.
•       Periodization of training by elite athletes is achieved with reductions in total volume, and a modest increase in the volume of training performed above the lactate threshold. An overall polarization of training intensity characterizes the transition from preparation to competition mesocycles. The basic intensity distribution remains similar throughout the year.

And from the commentary on the above paper by: Stephen A Ingham:

But just as vestiges reside in species, high performance training programs contain residual imperfections. The current paper highlights, in my opinion, the most common mistake: the accuracy of training execution. Specifically, this paper supports my own observation that for endurance athletes (particularly middle-distance), low-intensity training is performed too high whilst high-intensity training is performed too low. I surmise that the latter is a product of the former. The case studies illustrate the effects of including higher volumes of accurately performed low-intensity training It is not clear whether low-intensity training is more effective than high intensity training or whether low-intensity work simply allows more rapid recovery and preserves high intensity systems for performance of high-end work.

When working with middle and long distance athletes, this bunching of intensities on the plot of percentage of training time vs intensity is the first thing I look for when establishing a profile and understanding of ways in which preparation and performance can be improved. Further, there is a tendency for sports physiologists to prescribe types of sessions to an athlete with inadequate knowledge of the athlete’s program or how it is performed.

So get in more LSD. Keep the HIT well defined and to about two sessions per week. Ensure that LSD is LSD and HIT is indeed HIT.