Friday, November 16, 2018
Monday, October 8, 2018
Decade or so ago sports shoes manufacturers made claims for their products which would include how their shoes protect against shock generated by contact with the ground. Many of these claims related to patented materials which were strategically incorporated within the shoes themselves. Now advertising is less likely to contain these claims as scientific research has shown more often than not such addition to shoes are more likely to contribute to injury than prevent them from occurring. Credible Australian research would indicate sport shoes with air pockets in their soles could be leading to sports injuries. Basketball players were found to be four times more likely to suffer ankle injuries when they wore trainers with air pockets in their soles. The ankle injury rate was 3.85% per 1000 of the participants. Failure to warm up properly before competition was also a factor likely to increase injury and players with a history of previous injury were more likely to suffer a reoccurrence. Over half of those injured did not seek professional help. An independent Australian study of basketball players previously reported ankle injuries accounted for the greatest, single reason for missing play. Cells are in the heels and soles of sports shoes have been thought previously to provide worthwhile cushioning to the athlete. The report's authors suggest the air cells may make the rear foot less stable, increasing the risk of twists and sprains as players jump, turn and land. Compressed air is used in shock absorbing systems such as air breaks in big trucks. The air is allowed to evacuate slowly under pressure, and then returned by pumping it back into the cavity for the next impact event. Unfortunately this is not practical in terms of shoe construction and whilst many of the manufacturer’s claims are supported by laboratory studies, these do not always translate into practical applications in life.
In the 1990s there were several shock absorbing heels patented for comfortable business and dress shoes. The VectraSense Think Shoe simply called the Raven Think Shoe was designed by its inventor Ronald Demon. The Raven has a small computer embedded in the sole of each shoe which senses the difference between running and walking. Within 2 seconds, the shoe adjusts using an inflatable bladder to meet your new footgear requirements, according to the manufacturers. By changing the heel ground interface greater shock resistance is available with high peak heel strikes during running (up to middle distance) then slower pace reverts the shoe heel back to normal. The shoes require "AA" batteries but future plans are being made to power the system by some other means.
On the topic of yester-year wearable technology.
The Dada Sprees Supreme athletic shoes had a "spinnah" built into the outside wall of the shoe just above the ankle. When pressure was placed on the heel as with walking or jumping the spinner moved. The shoe was created when Dada Supreme partnered with NBA player, Latrell Sprewell . The Sprees enjoyed a certain vogue among members of the hip-hop community but now are confined to collectors.
Parasitic Power-Harvesting in Shoes?
Wednesday, October 3, 2018
The Greeks were the first ancient nation to acknowledge the importance of corporeal exercise. Athletic games and religion became the central parts of the lives of the ancient Greeks and a key ingredient of many religious festivals. Distance was important and the human foot was key in all measuring systems.
The ancient Egyptians had used a "step" for a measurement and a two-step stride was equivalent to two yards (1.8 meters). The ancient Greeks adopted this and a distance of 100"steps" (about 200 metres) became a stade. This was a popular distance for foot races and runners sprinted for 1 stade.
Amphitheatres where foot races were held were called a stadium and were 192m long and 32 m wide.
The ancient running course was a rectangular field marked off at each end by stone blocks set into the ground in a line or sill called a balbis. The balbis usually had parallel grooves carved along its length, as well as sockets at regular intervals for posts. The posts in the balbis served a dual purpose, as part of the starting gate and as turning posts (kampteres). The grooves marked the positions for the runners' feet. Runners had a standing start with the left foot slightly ahead of the right. The back end of the starting grooves was vertical to allow the runners to grip with their toes and shove off, whereas the forward end was bevelled toward the track to keep the runners from stubbing their toes.
In the city of Corinth, they experimented with the form of the starting line in their stadium, built ca. 500 B.C. The balbis was curved so that in races with turns the runners on the outside did not have to run farther than those on the inside. Also the runners placed their toes into individual toe grooves, not a continuous groove along the sill. The front and rear grooves were two or three feet apart, indicating the runners employed a wide starting stance. Races were started with a trumpet blast or auditory cry. The starter had a whip with which to beat the athletes who started too soon or broke the rules.
To prevent cheating circa 450 BC foot races started from mechanical starting gate or hysplex. Between poles at each end of the balbis, ropes were stretched to form a barrier. Using torsion from twisted ropes, the gate was lowered to the ground, then raised against the tension and kept in a vertical position by a ring and cord fastened to larger stationary posts at each end. The rings were also attached to ropes and held by an official standing behind the runners. At a jerk of the ropes, the rings slipped off the poles, and the gate slammed forward, allowing the runners to spring onto the track. Footraces included a double stade (or diaulos) in which runners raced up the field, turned around a post, and returned; the dolichos, (literally the "long race"), was seven to 24 stades in length (1,400 to 4,800 meters). In the diaulos runners had individual turning posts and two lanes for the run up the track and back. Coloured dust was used to mark off the lanes. For the dolichos the runners turned around single posts at each end.
In the stadium at Nemea (circa fourth century BC) there was a stone block with a socket hole 5.3 meters on the track side of the balbis and 3.4 meters to the west of the central longitudinal north-south axis. The socket hole held a turning post, and a similar one must have existed at the other end of the stadium. It is surmised runners clustered to their right as they approached the posts at each end.
An armed race or hoplitodromos was used as part of military training. Runners ran a diaulos with full body armour (estimated 25kg), including helmet, shin guards and carrying a shield. The 200metre (656 ft), foot race was the only event in the first 13 Olympiads. Runners wore loin cloths but later appeared naked. Any tricks bribery, or force employed by competitors to gain advantage upon others were strictly prohibited.
As time passed the Greeks added different events with the pentathlon and wrestling first introduced at the 19th Olympiad. Later in Roman times a Roman mile or mille passum (1000 double paces or strides) measured about 5000 feet or a little short of today’s mile (5,282 feet). In the beginning competitors ran barefoot but as the Greek Empire extended more athletes from colder climates came to races wearing sandals. At first spectators and barefoot competitors treated these as a novelty and sign of parochialism. As soon as shod athletes became winners then public opinion changed and the wearing of sandals was viewed with great suspicion and associated with cheats.
Eventually once it was recognized the sole of the sandal increased ground traction and propelled the leg forward with greater efficiency most athletes adopted the running sandal. The sole of the sandal needed to be securely attached to the foot and this necessitated leather thong wrapped to the ankle and sometimes above.
References Guhl E Koner W 1994 The greeks:their life and customs London:Senate
Hanna A 1985 Design in strude: Explorations in shoe design Industrial Design Jan/Feb pp40-45.