Stride Angle - Secretariat to Zenyatta

Someone posted this on ABR. I thought it was interesting so am "borrowing" the link ....

Click here for full article: Secretariat’s Big Stride Angle

There’s a lot of debate about what makes for a fast thoroughbred. Is it breeding? Heart? Training? Or a good jockey?

Stride Angle

The stride angle is the maximum opening between the front and rear legs, usually occurring at push off from the rear foot. We have found that for every degree you increase the stride angle, you increase the stride length by 2%. This means that if you increase the stride angle just 10°, you will cover 20% more ground with each stride.

It’s very difficult to catch up with someone who is covering 20% more ground than you are with each stride. In five strides, he or she will be a full stride length ahead of you. In twenty strides, they will be four stride lengths ahead of you.

Secretariat

When we learned that Secretariat won the Belmont Stakes in 1973 by 31 lengths and ran the fastest 1 1/2 miles on dirt in history (2:24 flat), we were intrigued. The conventional explanation for Secretariat’s success was that on autopsy his heart was found to be three times the normal size for his breed. But we have found that the ‘conventional explanation’ for athletic success is always based on strength and endurance, and never on stride efficiency. So we searched for some photos of Secretariat’s stride angle, and we found that it was 110°.

Barbaro

Barbaro won the 2006 Kentucky Derby by 6 ½ lengths, but suffered a fatal injury when he broke his right rear leg during the Preakness. Barbaro’s stride angle was 105°.

Affirmed

Affirmed won the Triple Crown in 1978 (the last horse to do so) with a 93° stride angle.

Forego

Forego is listed as #8 in the top 100 racehorses of the 20th century, with a 90° stride angle.

Man O’War

Over his two-year career, Man o' War won 20 of 21 races, setting three world records, two American records and three track records. Although he was ranked by some as the best thoroughbred of the 20th century, his times were slower than Secretariat’s. We suspect that his competition in the early part of that century was not as good as Secretariat’s in the 1970’s. His stride angle was 88°.

Distance Man O’War Secretariat

6 furlongs 1:11 1/5 1:09 4/5
1 mile 1:35 4/5 1:33 2/5
1 1/16 1:44 4/5 1:42 4/5
1 1/8 1:49 1/5 1:45 2/5
1 3/16 1:56 3/5 1:53 2/5
1 ¼ 2:01 4/5 1:59 flat
1 3/8 2:14 1/5 2:12 1/5
1 1/2 2:28 4/5 2:24 flat
1 5/8 2:40 4/5 2:37 4/5

Seattle Slew

Seattle Slew won the Triple Crown in 1977 with a stride angle of 83°.

What determines the stride angle?

It is plain to see that Secretariat had the biggest stride angle of any thoroughbred, which is why he has such a legendary position in horse racing. He was able to cover more ground than his opponents, which led to his stunning victories and phenomenal speed.

The stride angle is a result of the amount of microfibers (scar tissue) in the connective tissue surrounding the muscles of the legs.

Each muscle is surrounded by a thin membrane of connective tissue. Inside the body, the muscles never touch each other. Instead, the membrane of one muscle slides along the membrane of the adjacent muscle. The role of the connective tissue is to facilitate this sliding, which has to take place in order for the muscles to stretch.

The connective tissue between the muscles (fascia) serves the same purpose as cartilage does in a joint. In a joint, adjacent bones never touch each other. The end of each bone is covered with cartilage (another form of connective tissue), which provides a smooth, slippery surface to facilitate the movement of the bones.

In the same way, the connective tissue between the muscles facilitates movement.