About , the Digital Training Partner.
The power or force the accelerometer measures is a function of – the speed or velocity of the arm or leg or missile when it hits the target, and the mass or weight behind the arm punch or leg kick when it hits the target.
It can be seen from the force and power equations below that the force increases if the mass or weight behind the strike or hit increases, and if the acceleration (rate of change of speed or velocity) or speed increases.
The Digital Training Partner accelerometers are useful in measuring acceleration.
The units g imply the accelerometer is measuring the acceleration in terms of the acceleration due to gravity g. For example 4g,would be 4 times the acceleration due to gravity g.
To confirm the veractiy of the Digital Training partner, tests we conducted at the presitigious UCLA in the United States: A statistical correlation between action and measurment accuracy was indeed measured, verfified and confirmed.
A graph was drawn to get the relation between accelerometer reading and weight ( F= ma ), to in effect calibrate the accelerometer readings.
The Digital Training Partner Boxing Combat sensor can be moved in various ways. The sensor could be held lightly (so that there is minimum force on the sensor through holding it) and moved at a constant or unchanging (not accelerating) speed to see if the accelerometer gives a reading for constant speed. Further the sensor could be moved from fast to slow (decelerating) and slow to fast (accelerating) in the air, to see if it gives readings for these non impact movements. This functionality is useful in the parctice of kata, to measure the snap at the end of any punch or kick.
We have witnessed boxing fights, karate competitions, Tae Kwondo bouts, UFC cage fights and witnessed non scoring hits, missed not scoring points.
Therefore if the fighter was wearing the Digital Training Partner Boxing Martial Combat sensor on a target area or areas, the sensor accelerometer would be able to register that impact and the size of that impact. Thus blows that hit the target can be separated from blows that miss.
The maximum that could be measured is about 100g. This level is high. And a strike of this impact would be harmful. The casing on the sensor is strong enough to not break with strong direct impact punches.
A 1985 study of Frank Bruno, who would go on to be WBC heavyweight champ, showed he could punch with a force of 920 pounds in the lab. In the US force is measured in pounds. Researchers extrapolated that to a real life blow of 1420 pounds, enough to accelerate his opponents head at a rate of 53 g, that is 53 times the force of gravity.
If an accelerometer is put in a glove, it could measure the force of the fist when a blow is delivered but that would depend on where the accelerometer is put e.g.it could be in the palm (taped or otherwise), wrist and so on.
Placement of the sensor is vital = if you place the sensor as the target it will read highly and give you an exaggerated sense of your power. Placing the sensor inside a glove will dampen the reading and burried in a punching bag, more again. Therefore the force the glove delivers would be the accelerometer reading, less the force absorbed by the glove, tape or other things, depending on where the accelerometer was put relative to the main force of impact of the punch.
The position the accelerometer sensor is in, could be determined by the type of fight or situation e.g amateur or professional fights might not allow the placing of objects in the gloves,especially on the fists.
Consistent placement of the Digital Training Partner Boxing Combat sensor is imperitive to record consistent results that are comparable. Measurements with barefist will be different than with glove, and similarly hitting the sensor will yield a higher measurment than hitting the proximity.
The effect of padding in the gloves, protective head gear and punching bags on the force of the punch or hit, can be estimated as follows. For the effect of the padding in gloves, a sensor can be placed (e.g taped or bandaged) on the fist, inside the glove and another sensor can be placed on the outside of a heavy punching bag, or so that force is not absorbed by the punching bag moving, or on on a hard surface such as a wall.
The effect of the padding=force reading of accelerometer sensor on fist inside glove-force reading of sensor on outside of glove on punching bag or wall. Placing the accelerometer sensor directly on the outside of gloves would lead to the sensor case being smashed or cracked and so rendering the sensor useless.
The force absorbed=sensor force reading on outside of bag-sensor force reading on inside of bag .In theory by estimating the force absorption of gloves and punching bags, and protective head gear, the real force of the blow can be estimated.
An alternative approach to the absorption of force by the padding is the following equation
Real force=force measured by accelerometer sensor inside padding of a punching bag+force absorbed by padding. Approximately speaking, the real force of the blow such as a punch, kick or hand hit,could be said to be proportional to the force measured. In other words as the measured force goes up or down,the real force proportionally goes up or down. For boxing gloves the following equation can be considered
Real force=force measured by accelerometer sensor on outside of padding of glove for example on target or large punching bag+force absorbed by the padding.
To measure the force of a blow, hit or kick on a punching bag, the sensor can be taped or bandaged onto the bag, or put inside the bag,and the fighter can target the sensor to get an estimate of how hard they hit. However, more than one sensor can be applied to a punching bag, in different configurations or patterns on the bag e.g one on vertically top of the other,so that the fighter has a range of targets to hit or kick.
To ensure consistency of measurements and so that accelerometer sensor measurements can be accurately compared to one another, it is important that the sensor is placed in the same place on fist,palm or wrist or punching bag or target, in the same way, e.g tape, bandage, Velcro or large, tight elastic type band.
If the accelerometer sensor is not directly hit,or there is no direct impact of the blow on the sensor,but the computer gives an increased reading the harder the blow, then the computer reading is proportional to what the direct hit sensor reading would have been.Such a situation could arise if the sensor was inside or on the base of the punching bag, or in the palm or wrist of a fighter, with or without gloves,or in the inside of head protection gear.
To calculate the mass or weight behind and therefore force behind punch is difficult since the punch, hit, kick or blow, is the result of many muscles working together, plus the weight of the body behind the punch. The extent of weight of the body behind the punch could depend on technique, so that the better the technique the more the weight and muscles behind the blow.
Despite appearances, a well delivered punch ot blow, is a whole body movement.
A punch can be a result of a kinetic or movement energy that starts at your feet,travels up your leg, into and through your hips and core upper muscles, and then along your arm via the chest and shoulders.Some variation in this can occur depending on whether the punch or blow is boxing,martial arts, jab, cross, upper cut or hook. Each punch you throw,uses the same muscle groups, but each one places a slight emphasis on one muscle or another.
For boxing punches the power is initiated in the bent toe,then the ankle,up to the calf, thigh, hip, lower back/abdominals, lats, shoulder/chest and finally through the tricep.The triceps are a group of three muscles on the back of the upper arm, and they extend your arm and drive you forward. The biceps are for speed and snap of your hooks and upper cuts. Snap means the quick backwards and forwards movement of the arm. Your abdominals allow you to connect the force generated by all your limbs, into one powerful punch. The terms ‘lower lats’ and ‘high lats’, are used to describe back muscles like Latissimus Dorsi.
One metric for gauging the risk and seriousness of a brain injury is the Wayne State Tolerance curve, which looks at both the g-force imparted to the head,and the span of time involved. Generally speaking you don’t want to take a shot of more than 50g,although you can stand more if the impact is really brief–say,couple of thousandths of a second. Hence the force of the blow felt by the target,depends not only on the muscles and body weight behind the blow,but also on time of impact of the blow hitting the target.
The longer the time of impact, the more force will be transferred from the hitter to the target.
An accelerometer is an electromechanical device used to measure acceleration forces. Such forces may be static, like the continuous force of gravity,or,as is the case with many mobile devices, dynamic to sense movement, falling or vibrations.
Acceleration is the measurement of change in velocity, or speed divided by time. Therefore if the accelerometer is moved at constant or nonchanging speed it may not give a reading, as above.
Some useful equations are:
Newtons Second Law: Force=mass*acceleration.
Momentum: p=mass*velocity
Work or Potential Energy:E=Force*distance or
E=mass*acceleration due to gravity*height
Kinetic or movement energy K.E=(1/2)*mass*velocity*velocity
Power=force*velocity=E/t=rate of change of energy.
Pressure=force/area=force per unit area.
The law of conservation of things like energy and momentum says that energy is transferred from one source to another, and cannot be lost or destroyed.Therefore the hit from a hand or foot,would transfer most of it’s energy or momentum to the target e.g punching bag, depending on what sort of impact there is and how long the impact is. The energy or momentum transferred, is partly absorbed by the punching bag,and can be seen in the possible swing of the bag or pendulum, and sound of the impact.
A fighters fist or glove will have a force dependent on how fast the fist or glove is speeding up, and the effective mass behind the punch, when the punch reaches the target or punching bag. The effective mass is the mass when the strength of the muscles working together, and the weight of the body behind the punch or hit, are taken into account.
Alternatively, the sensors could be velcroed to the base of a punching bag,where it might measure the movement and force absorbed,of a punching bag. This assumes that the more the punching bag moves,the harder the blow on it. However the bag can be pushed rather than just punched. A push might not measure the force of a punch or kick. Further, the mass of the bag would have to match the accuracy of the acceleration reading. A big bag would have low acceleration, and may read values smaller than the error bars of the accelerometer. Small bags might accelerate faster, than the accelerometer chip can get a reading,and might be higher than the maximum reading. The way to get the sensors to work accurately might be to have a punching bag of just right size and weight, so that the force absorbed and movement of the bag is directly proportional to the real or effective force of the blow.
A study of seven Olympic boxers in weight classes ranging from flyweights to super heavyweight showed a range of 447 to 1066 pounds of peak punching force.Energy or force transferred from punch to target varied widely depending on how heavy the force behind the boxers hands and gloves were, how fast they punched,and how rigidly they held their wrists.
Martial arts punches are generally thought to involve much less force than boxing. A study of 12 Karate black belts showed so called reverse punches delivered an average force of 325 pounds,with the strongest measuring 412 pounds. Another study found martial artists needed 687 pounds of force to break a concrete slab 1.5 inches thich. Short range power punches averaged 178 pounds.In these studies the values given depend on methods used to measure them, which might not be accurate. However, generally boxers, especially heavy boxers, seem to have stronger punches, than martial artists.
Use the Digital Training partner in:
gradings, point sparing, pre-fight training, reflex training failure comparison in groups, teaching beginner, kata education, physics studies, tennis, golf, medicine, peridonetery, orthopeadics and more.
