Effects of moment of inertia on restricted motion swing speed

In many sports, the maximum swing speed of a racket, club, or bat is a key performance parameter. Previous research in multiple sports supports the hypothesis of an inverse association between the swing speed and moment of inertia of an implement. The aim of this study was to rigorously test and quantify this relationship using a restricted swinging motion. Eight visually identical rods with a common mass but variable moment of inertia were manufactured. Motion capture technology was used to record eight participants' maximal effort swings with the rods. Strict exclusion criteria were applied to data that did not adhere to the prescribed movement pattern. The study found that for all participants, swing speed decreased with respect to moment of inertia according to a power relationship. However, in contrast to previous studies, the rate of decrease varied from participant to participant. With further analysis it was found that participants performed more consistently at the higher end of the moment of inertia range tested. The results support the inverse association between swing speed and moment of inertia but only for higher moment of inertia implements

The effect of moment of inertia on the speed of swung implements.

The maximum swing speed of an implement is an important performance parameter in many sports. It is understood that moment of inertia (MOI) has an effect upon the swing speed of an implement and numerous studies have found a similar rate of swing speed decay (n). These studies considered different movements which suggested that skill was less important than physique to the relationship between swing speed and MOI. The aim of this project was to quantify this relationship and to determine whether the physical characteristics of a participant can be used to predict their swing speed performance. A series of eight visually identical rods with varied MOI were swung in a heavily restricted, maximal motion and trials were recorded with a motion capture system. The results found that swing speed decreased as MOI increased. It was also found that if n was assumed to be constant, the maximum work done by a participant was strongly and significantly related to their swing speed. The relationship between work done and swing speed was used to create a model to predict swing speed for an implement with a specific MOI. This model was validated for a new set of participants performing the same restricted motion and all measured data fell within the confidence intervals of the predictions. The ecological validity of the model was tested in an analysis of the swing speed of tennis groundstrokes. An impact model was used to analyse the effect of changing MOI on ball speed. It was discovered that there is an optimum MOI that produces a maximum ball speed and that this optimum MOI is dependent upon n. This makes the customisation of equipment a realistic possibility. A simple method for measuring n in a non-laboratory environment is proposed that will enable the customisation process to take place

Effect of moment of inertia and physical profile on restricted motion swing speed

The maximum swing speed of an implement is an important performance parameter in many sports. It is understood that moment of inertia (MOI) has an effect upon the swing speed of an implement and numerous studies have found a very similar relationship between swing speed and MOI. These different studies considered different movements which suggested that skill was less important than physique to this relationship. The aim of this work was to quantify the relationship between swing speed and moment of inertia and to determine whether a participant's physical characteristics are related to their swing speed performance. A series of eight visually identical rods, with varied MOI were swung in a heavily restricted, maximal motion. Feedback was supplied to the participants about their motion and all trials were recorded with a Motion Analysis Corporation motion capture system. The results found that a similar exponential relationship exists between swing speed and MOI. It was also found that a participant's maximum work done is significantly related to their swing speed. This is a relationship that could be used to predict a participant's swing speed for a specific MOI implement. More work is to be carried out on a larger population in order to be confident in the power of the relationships found

Investigating the relationship between swing weight and swing speed across different sports using historical data

In many sports, the maximum swingspeed of a racket, club or bat is a key performance parameter. Previous research has suggested that a logarithmic relationship exists between the resultant swingspeed and the swingweight/moment of inertia of the implement. However, these studies have only focussed on one specific sport and relatively little is known about the effect of swingweight on swingspeedacross the wider spectrum of sport. Data was collated on the swingspeeds achieved in numerous sports that employ an implement and a swinging motion. A range of typical swingweights were determined for the various implements and the data normalised to common conventions such that comparisons could be made. This meta-analysis established a new relationship between swingweight and swing acceleration, valid across the wide range of implements considered. This relationship was found to be of the form a=C/Im, where C is a player constant and m=0.59 (p<0.01)