Saturday, February 2, 2008

New England Patriots’ Midwinter Blues

In spite of putting together a perfect regular season, the Patriots' performance has often been questioned as their margin of victory declined. Was this just coincidental or is there a systematic trend at work that makes it difficult to maintain peak performance throughout the course of a complete football season? Dr. Michael Holik has stated that Human skin exposed to sunlight on cloudless days in Boston (42.2 degrees N) from November through February produced no previtamin D3. Could an insufficiency of Vitamin D be the cause of the Patriot's drop off from peak performance?

The pro football season starts in late summer and ends in the dead of winter, spanning a wide variation in solar intensity as measured by the Ultra Violet (UV) Index. An earlier post, Sunshine and Super Bowl XLII, noted southern teams have a bit of an edge for multiple Super Bowl wins. New York and New England are both northeastern teams and both have comparable declines in solar exposure as the season wears on. Is there a drop off in performance, as sunshine gets too weak to produce Vitamin D? More specifically, has there been any difference between the Patriots’ and Giants’ performance relative to the UV Index (UVI) over the course of the season?

The New England Patriots played their pre-season games at Tampa (UVI estimate = 11.7); versus Tennessee (7.5); at Carolina (8.8); and versus the New York Giants (6.9). The Pats started the regular season at the New York Jets (5.0) with a five-week moving average UVI of about 8.0. As the schedule unfolded in the fall, the UVI average steadily declined to 5.0 at the end of September; 4.5 at the end of October; 2.0 at the end of November; 1.5 at the end of December. Home field advantage kept the Patriots home in January and didn’t help with sun exposure.

Figure 1 summarizes the New England Patriots’ points scored, points allowed and total points over the course of the season as a function of the estimated 5 week moving average of the UV Index. A linear fit of the data is also shown to illustrate trends, though correlations are small since scores in any football game have a big standard deviation of approximately 14 points around the line. The trend lines show that the offense scored fewer points on average as the UVI declined, while the defense gave up more points. The Patriots had started the season blowing out opponents and beating the spread by a wide margin. While they ended the season unbeaten, the games were often much closer and results often fell short of Vegas’ expectations.

The New York Giants UVI also started high (7.8) and declined as expected during the fall into winter. However, the Giants had two playoff games in January that took them to Tampa Bay and Dallas where the solar intensity was much greater than what the Patriots experienced at home. The Giants’ offensive production trend (shown in Figure 2) decreased slightly as the UV Index declined. On defense the trend actually improved a bit (allowed fewer points) as a function of decreasing UVI.

Figure 2. Giants’ Offense Has Declined Slightly as UVI Declined.

With the Patriots’ 5 week moving average UVI currently at 2.0 they should win 32.4 - 18.0 over an average opponent. In contrast, the Patriots’ overall season average score was 35.6 - 17.0, Therefore based on UVI the Pats should under perform by 3.2 points on offense and 1.0 points on defense or a total of 4.2 points. As a result of the playoff games in the south, the Giants’ 5 week moving average UVI is currently 2.9. The linear fit in Figure 2 suggests they should beat an average opponent by 22.8 – 20.7. In contrast, the Giants’ overall season average score was 23.2 – 21.2. The Giants would be expected to under perform on offense by 0.4 points but make it up on defense. UVI exposure would appear to favor the Giants by nearly 4 points… not enough to offset the 12.5 point line for the game, but enough perhaps to make the game interesting.

While there isn't enough data here to draw any firm conclusions, the noticeable drop in the Pats' offensive production with declining UV Index levels suggests that Vitamin D levels could be a factor. Further research may shed light on this question but until then, Vitamin D should be monitored and supplements may be beneficial for maintaining peak performance.

Table 1. Sun Exposure Declines Substantially During the Football Season

Date NY Giants UVI (5 week) NE Patriots UVI (5 week)
Sunday, 9/9 at Dallas 7.8 at Jets 8.0
Sunday, 9/16 GREEN BAY 7.1 SAN DIEGO 6.8
Sunday, 9/23 at Washington 6.6 BUFFALO 6.5
Sunday, 9/30 PHILADELPHIA 6.2 at Cincinnati 5.0
Sunday, 10/7 NEW YORK JETS 5.9 CLEVELAND 4.5
Monday, 10/15 at Atlanta 5.4 at Dallas 4.6
Sunday, 10/21 SAN FRANCISCO 4.8 at Miami 5.1
Sunday, 10/28 at Miami (London) 4.5 WASHINGTON 4.4
Sunday, 11/4 BYE 4.1 at Indianapolis 4.6
Sunday, 11/11 DALLAS 3.7 BYE 4.2
Sunday, 11/18 at Detroit 2.9 at Buffalo 3.3
Sunday, 11/25 MINNESOTA 2.6 PHILADELPHIA 2.0
Sunday, 12/2 at Chicago 2.1 at Baltimore 1.9
Sunday, 12/9 at Philadelphia 1.9 PITTSBURGH 1.7
Sunday, 12/16 WASHINGTON 1.6 NY JETS 1.5
Sunday, 12/23 at Buffalo 1.4 MIAMI 1.6
Saturday, 12/29 NEW ENGLAND 1.3 vs NY Giants 1.5
Sunday, 1/6 at Tampa Bay 2.0 BY 1.4
Sunday, 1/13 at Dallas 2.2 JACKSONVILLE 1.4
Sunday, 1/20 at Green Bay 2.2 SAN DIEGO 1.4
Sunday, 1/27 BYE 2.4 BYE 1.5
Sunday, 2/3 NE Patriots 2.9 NY Giants 2.0

No comments: