The tragic death last week of Australian batsman Phillip Hughes drew worldwide attention and sympathy.It also refocused attention on cricket helmets and re-ignited the debate on whether they can be improved to further reduce injuries.In 2013, two cricketers died from injuries arising from being struck by the ball while batting. One was from South Africa and the other from Pakistan. They were struck on the head and chest respectively.
But being hit while batting is not the only way fatal injuries may occur. In 2007, an umpire was struck on the head by a ball and in 1998 a fielder was also struck by a ball. Both died.Most injuries in cricket, however, are not fatal. They can and do shorten and bring a premature end to careers. The top ones are hamstring strains, low back issues and strains to the side, shoulder and ankle. The most susceptible are fast bowlers.
This has led to the use of biomechanics to study bowling actions and the injuries arising from them. Biomechanics is the application of mechanical principles to biological systems and of particular interest is the study of how the human body reacts when mechanical forces are applied to it. The field is not new, though new tools, technologies and techniques are being developed using engineering and physiological principles.
Japanese martial artists probably led the way in applying physics to hand-to-hand combat. The principles of levers, fulcrum, forces and energy transfer were artfully and effectively applied to the techniques of jujitsu, judo, aikido and karate with deadly efficacy. Human impact engineering is a recent field and looks at the effect of auto collisions on the person.
Cricket is in essence the art of energy transfer. A bowler runs in and imparts energy to a ball as he bowls to the batsman.The batsman, providing he does not leave the ball alone, either dissipates the energy by playing a defensive stroke (thereby absorbing some energy) or increases it by hitting it firmly (thereby transferring the bat energy to the ball). Biomechanical principles are critical to accomplish these outcomes.
The application of biomechanics to the delivery action of fast bowlers is a very active field of research. They sprint in and jump before delivering the ball. Their ankles, knees and lower back thus bear the brunt of the forces generated by the impact as they land in their delivery stride. The use of high-energy absorption boots is necessary. The bowlers' boots of today are a far cry from those of the past.
Some of these technologies are common among sports that involves rather large people jumping and landing on firm surfaces on a regular basis like bowlers and basketball players.
Fast bowlers need not only the speed of the run-up but also arm speed, be it round-arm or slinging action, in order to generate the necessary speeds, which may be in excess of 90 miles per hour and can reach 100 miles per hour on occasions. Usain Bolt clocks just under 28 miles per hour. So if the world's fastest man were to run up to bowl and he just let the ball go, it would be way slower than the speed of balls bowled by a slow spinner.
It is thus clear that the speed has to be generated by the arms and upper body. Understanding the biomechanics of this motion is key to preventing injury to bowlers. A cricket ball which weighs between five and a half and five and three quarter ounces and travelling at 90 miles per hour can cause serious injury to a human being, especially if the body absorbs the total energy of the impact.
It can cause serious internal damage. This happens when it strikes a soft area are like the neck. This is the principle used in karate.