Task 3: Sally Pearson
1. Explain the the concepts of acceleration and deceleration:
Acceleration is the rate at which an object changes its velocity; the rate at which an object speeds up or slows down. If the object speeds up then it has a positive acceleration, and if it slows down that means it has a negative acceleration, which is deceleration and can also be called retardation. Acceleration is also a vector quantity as it is the rate of change of velocity. In brief, acceleration refers to rate of change in velocity and its positive value signifies that the speed of a moving object is increasing while deceleration is the opposite of acceleration and it applies when the speed of an object is decreasing. The standard unit to measure acceleration is metre per second squared (m/s2 or ms-2).
Acceleration = change in speed
time taken for the change
2. Using the athlete as an example students describe their chosen athlete/ athlete’s sport in terms of acceleration, deceleration
a) Details of the athlete's personal best in terms of acceleration:
Sally Pearson's personal best in terms of acceleration is 2.025 m/s/s.
b) How acceleration / deceleration are important in fast take offs, catching opponents by surprise, overtaking competitors, design of equipment, frictions etc:
Acceleration is significantly important in hurdles in numerous ways. Upon hurdle clearance, there is a need to reaccelerate. This will occur after each clearance. Speed should be generated when coming off the hurdle. The motion of hurling should give the athlete a boost so that when they touch down they are able to accelerate out of the hurdle.This is important as there is greater speed when you have faster acceleration because you are increasing speed. Acceleration is also a major factor in fast take offs, because the event is only 100 m hurdles it is the ability to achieve maximum velocity within the shortest time frame that is more important than the maximum velocity itself. That is, acceleration rather than maximum velocity is of greater importance. By the athlete having a good takeoff, it sets up the ensuing acceleration by leaving the athlete in a position to continue. If the takeoff action was poorly executed, the athlete will need to recover from it during landing. Deceleration becomes a factor after an athlete passes their point of maximum speed. Deceleration occurs from the eigth hurdle to the finish line, which is the point in the race where mental breakdowns can come into play and technical flaws are exposed. Reflexes slow down and it is possible for hurdlers to lose their ability to react to barriers. At this stage in the race, there is no way to avoid decelerating and it is important to keep the upper body relaxed , to maintain efficient sprinting from between the hurdles and to maintain efficient hurdling from over the hurdles. Clearing the last hurdle is critical as it becomes more difficult to recover when hitting hurdles and following the last hurdle is the sprint over the finish line.
1. Starting line to the third hurdle (Acceleration)
2. Fourth hurdle to seventh hurdle (Top speed)
3. Eighth hurdle to finish line (Deceleration)
c) How acceleration on the sport is measured:
Hurdle acceleration is measured at the start of the race by the change in the athlete's speed from stop to go, and the time that is taken for the change in speed to occur. It is also measured through the ability of the athlete to gain speed after the completion of each hurdle, i.e. accelerating through the hurdles.
d) Factors that may contribute to or hinder the acceleration/deceleration of an athlete in their chosen sport:
- A bad take off
- Hitting hurdles.
- Landing off-balance.
- Twisting the hips and shoulders/ rotating body.
- Coming down after a hurdle and planting takeoff leg in the centre of the track.
Acceleration is the rate at which an object changes its velocity; the rate at which an object speeds up or slows down. If the object speeds up then it has a positive acceleration, and if it slows down that means it has a negative acceleration, which is deceleration and can also be called retardation. Acceleration is also a vector quantity as it is the rate of change of velocity. In brief, acceleration refers to rate of change in velocity and its positive value signifies that the speed of a moving object is increasing while deceleration is the opposite of acceleration and it applies when the speed of an object is decreasing. The standard unit to measure acceleration is metre per second squared (m/s2 or ms-2).
Acceleration = change in speed
time taken for the change
2. Using the athlete as an example students describe their chosen athlete/ athlete’s sport in terms of acceleration, deceleration
a) Details of the athlete's personal best in terms of acceleration:
Sally Pearson's personal best in terms of acceleration is 2.025 m/s/s.
b) How acceleration / deceleration are important in fast take offs, catching opponents by surprise, overtaking competitors, design of equipment, frictions etc:
Acceleration is significantly important in hurdles in numerous ways. Upon hurdle clearance, there is a need to reaccelerate. This will occur after each clearance. Speed should be generated when coming off the hurdle. The motion of hurling should give the athlete a boost so that when they touch down they are able to accelerate out of the hurdle.This is important as there is greater speed when you have faster acceleration because you are increasing speed. Acceleration is also a major factor in fast take offs, because the event is only 100 m hurdles it is the ability to achieve maximum velocity within the shortest time frame that is more important than the maximum velocity itself. That is, acceleration rather than maximum velocity is of greater importance. By the athlete having a good takeoff, it sets up the ensuing acceleration by leaving the athlete in a position to continue. If the takeoff action was poorly executed, the athlete will need to recover from it during landing. Deceleration becomes a factor after an athlete passes their point of maximum speed. Deceleration occurs from the eigth hurdle to the finish line, which is the point in the race where mental breakdowns can come into play and technical flaws are exposed. Reflexes slow down and it is possible for hurdlers to lose their ability to react to barriers. At this stage in the race, there is no way to avoid decelerating and it is important to keep the upper body relaxed , to maintain efficient sprinting from between the hurdles and to maintain efficient hurdling from over the hurdles. Clearing the last hurdle is critical as it becomes more difficult to recover when hitting hurdles and following the last hurdle is the sprint over the finish line.
1. Starting line to the third hurdle (Acceleration)
2. Fourth hurdle to seventh hurdle (Top speed)
3. Eighth hurdle to finish line (Deceleration)
c) How acceleration on the sport is measured:
Hurdle acceleration is measured at the start of the race by the change in the athlete's speed from stop to go, and the time that is taken for the change in speed to occur. It is also measured through the ability of the athlete to gain speed after the completion of each hurdle, i.e. accelerating through the hurdles.
d) Factors that may contribute to or hinder the acceleration/deceleration of an athlete in their chosen sport:
- A bad take off
- Hitting hurdles.
- Landing off-balance.
- Twisting the hips and shoulders/ rotating body.
- Coming down after a hurdle and planting takeoff leg in the centre of the track.