Wax & Equipment Changes vs. Race Times, 1924->

The following graph shows the trend in times for the men's 50km classic Olympic/VM event vs Boston Marathon, 1924-present. I wanted to see if it was possible to isolate equipment/wax-related improvements in time from training/nutrition-related. 

I made the assumption that marathon running represented the purest example of a sport where equipment developments have had the smallest impact on the improvement in time (debatable I am sure).  I then took the difference between the ski time trend (orange) and the running time trend (blue).  You have to look at trends because as we know snow conditions can vary widely day-to-day.

The green lines are a proxy for equipment/wax-related improvements in 50k times. I've highlighted the most impactful advances in technology that affected times, but there are many more. 

One other factor that bears mention is the improvement in grooming practices over the 20th century and the increased use of artificial snow on racing trails.  Courses have evolved from the army foot packing single-tracks to the first use of mechanical grooming at the 1960 Squaw games (without a noticeable improvement in times, which is no surprise to anyone who has skied the post-10am slop on east-facing trails in Tahoe - e.g. McKinney Creek), to the loop racing on artificial snow that we see now.  A firmer track is faster, and also allows for the tiny, light pole baskets that we use now.  The latter was one of the main drivers of change in ski technique over the years; high turnover with the equivalent of a waffle on the bottom of your pole is hard

I stopped the comparison in the late 80s because:

• the ski times start jumping around, and the data points are fewer,
• the difference between ski and running times trends to 0.  Ironically the 50k classic and men's marathon are both run at slightly over 2 hours now. 

Click on the graph to get an easier to view version

On the women's side it's hard to glean any insight on the equipment-related improvements in ski times because the ski race with the longest history is the 5k classic, which is essentially a sprint race, vs. a marathon running race.  However, it's interesting to look at the trend in times for the 2 events.  Women's Oly/VM XC racing began with the 1952 Oslo games, and unofficial/official Boston Marathon times were recorded from the late 60s.

Two observations from the chart below:

• HUGE improvement in times in the women's marathon early on.  Women historically had not run longer distances for a variety of reasons, the main one being the sexist notion that women were too "weak" to complete an event as long as a marathon.  SO, when women began running longer distances there was a big "training curve", if you will, that resulted in big gains from the K Switzer/Sara Mae Berman years to Joan Benoit
  
  
• Virtually no noticeable improvements in the 5km time in women's elite skiing. This partially has to do with the vertical scale of the graph, but consider that the time improvements due to laminated skis and synthetic waxes would have already been realized, AND, although women were not competing in the Olympics or World Championships in XC skiing before 1952, we can assume that they were competing locally/nationally, so it wasn't a "new" thing like distance running was.

Finally the entire dataset, including all distances and times (classic only) is HERE .  The colors represent the country of the winner.  Some observations:

• The Finns were the dominant ski nation in the first half of the 20th century.  One can speculate on the reasons, but one might be that Finnish equipment, even up through the 1970s, was often preferred by racers.  In short, the Finns made better stuff than the other Nordic countries.
  
  
• Sweden dominated in the 1948 St. Moritz Olympics and 1950 Lake Placid/Rumford World Championships likely due to their use of Swix' new synthetic waxes, which performed better than traditional tar-based waxes.  Swix was founded as a subsidiary of Astra AB, a Swedish pharma concern that is now part of AstraZeneca.
  
  
• The Russians/Soviet Union and other eastern bloc contries were awfully good in the 70s and early 80s for men, and until the early 80s for women.  The women have continued to excel (except a period that corresponds with the collapse of the Soviet system in the late 80s) but there have been few Russian male winners of classic events since the 1980s.  Leave it at that.  Any rants about doping in the comments will be deleted :-)