Incorporating subjective end-user perceptions in the design process: a study of leg guard comfort in cricket

During the design of sports equipment, the main focus is usually on physical performance attributes, neglecting key subjective factors such as feel or comfort. The personal protective equipment worn in sport is a typical example of where injury prevention has taken precedence over user comfort, but it is anticipated that, with an improved approach to the design process, comfort can be enhanced without sacrificing protection. Using cricket leg guards as an example, this study aims to develop a systematic method for assessing user perceptions and incorporating them into the design process. Using this method, players’ perceptions of the factors that influence comfort were elicited through the use of co-discovery sessions, focus groups, and individual interviews and analysed through an inductive process to produce a comfort model. The relative importance of the different comfort dimensions were identified through the use of an online questionnaire utilizing the analytical hierarchy process method. Through the combination of these methods, six general dimensions were identified with a weighting regarding the amount to which each one determines a user’s perceived comfort. These results demonstrate how subjective analysis can be integrated into the design process, allowing for end users’ preferences to be considered and integrated

Determining the effect of cricket leg guards on running performance

Modern-day cricket has experienced a shift towards limited over games, where the emphasis is on scoring runs at a rapid rate. Although the use of protective equipment in cricket is mandatory, players perceive that leg guards, in particular, can restrict their motion. The aim of this study was to determine the influence of cricket leg guards on running performance. Initial testing revealed that wearing pads significantly increased the total time taken to complete three runs by up to 0.5 s compared with running without pads (P < 0.05). In addition, we found that the degree of impedance was dependent on pad design and could not be solely attributed to additional weight. To assess possible causes of reduced running performance, a biomechanical analysis was performed, investigating running kinematics, stride parameters, and ground reaction forces. The results revealed that the widest pad had the greatest effect on running kinematics, increasing hip abduction and decreasing hip extension, resulting in a shortened stride length (by 0.10 m) and increased stride width (by 0.12 m) compared with running without pads. Wearing pads also significantly increased peak braking force (by up to 0.3 times body weight [BW]), braking impulse (by up to 0.012 BW · s−1), peak mediolateral force (by up to 0.17 BW), and mediolateral impulse (by up to 0.016 BW · s−1) compared with running without pads, which resulted in reduced force applied in the direction of locomotion. The consequence of this reduction in running performance is an increased risk of being run-out or a reduction in the number of runs that could be scored from a particular shot

Measurement of contact time in short duration sports ball impacts: an experimental method and correlation with the perceptions of elite golfers

The perception of ‘feel’ during a ball-implement impact is considered a significant determinant in equipment selection. Previous studies in golf have found that the perceived time for which the ball and clubface are in contact is a factor in the ‘feel’ of the shot. This factor appears to have become more significant with the development of the latest metal ‘woods’. The purpose of this study was to investigate whether golfers’ perceptions of impact duration correspond to measured values or whether the perceptions are created by other factors. A technique has been developed to measure the duration of impact by creating an electrical circuit in which the ball and clubface form a ‘switch’, completing the circuit whilst contact is maintained between the two bodies. Measurements were taken of the duration of impact between five different types of clubhead and two different constructions of golf ball. Further tests, also reported in this paper, investigated the effect of both clubhead speed at impact and ball compression on the impact duration. The results suggest that the ball has a greater effect on impact duration than the type of clubhead with lower compression balls producing longer impact durations than higher compression balls and two piece balls producing shorter impact durations than three piece, wound balls. It was also found that the duration of impact decreased as the clubhead speed at impact was increased. Finally, results suggest that there is no correlation between the perception of the golfer and the actual duration of impact and therefore other factors are responsible for creating this perception

Matching golfers’ movement patterns during a golf swing

The golf swing is a multidimensional movement requiring alternative data analysis methods to interpret non-linear relationships in biomechanics data related to golf shot outcomes. The purpose of this study was to use a combined principal component analysis (PCA), fuzzy coding, and multiple correspondence analysis (MCA) data analysis approach to visualise associations within key biomechanics movement patterns and impact parameters in a group of low handicap golfers. Biomechanics data was captured and analysed for 22 golfers when hitting shots with their own driver. Relationships between biomechanics variables were firstly achieved by quantifying principal components, followed by fuzzy coding and finally MCA. Clubhead velocity and ball velocity were included as supplementary data in MCA. A total of 35.9% of inertia was explained by the first factor plane of MCA. Dimension one and two, and subsequent visualisation of MCA results, showed a separation of golfers’ biomechanics (i.e., swing techniques). The MCA plot can be used to simply and quickly identify movement patterns of a group of similar handicap golfers if supported with appropriate descriptive interpretation of the data. This technique also has the potential to highlight mismatched golfer biomechanics variables which could be contributing to weaker impact parameters

Measurement and analysis of grip force during a golf shot

In this study, grip force was measured during a standard golf tee shot using two different measurement techniques. The first utilized a matrix-type thin-film sensor applied to a golf grip, from which total grip force could be readily determined. The second method involved 31 individual thin-film force sensors strategically placed on two golf gloves, allowing the force output of specific regions of the hands to be measured. Twenty golfers of varying ability participated in each test. The discovery of a unique grip force ‘signature’ for each golfer emerged from these data. That is, each golfer had a very repeatable total grip force trace, but these traces varied considerably between golfers. High-speed video was also recorded for many of the golfers tested so that key phases in the swing could be identified on the force traces

Evaluation of thin, flexible sensors for time-resolved grip force measurement

Three types of thin, flexible force sensor were studied under a variety of loading conditions to determine their suitability for measuring grip force. Static accuracy, hysteresis, repeatability, and drift errors were established, the effects of shear force and surface curvature were considered, and dynamic accuracy and drift were measured. Novel tests were developed to consider dynamic accuracy and sensitivity to shear loadings. Additionally, three sensors were evaluated in a real-life gripping scenario, measuring grip force during a golf shot. Comments are made on sensor performance, ease of use, and durability

Influence of modified driver properties on golfer movement patterns

Golfers can modify the mass and moment of inertia (MoI) of their driver. The influence of these changes on golfers’ unique centre of pressure and centre of gravity movement patterns were investigated. The patterns between the control and High Mass condition showed small differences to the High MoI and combined high MoI/Mass condition which may be similar to results seen in running footwear literature with substantial changes to shoe characteristics

Evaluation of vibrotactile sensations in the 'feel' of a golf shot

Players’ subjective perceptions of the characteristics, suitability and quality of sports equipment will have a significant bearing on their equipment selection. The ‘feel’ of a golf club is such a perception and the vibration at impact perceived by the player is generally considered to contribute significantly to ‘feel’. The aim of this study was to investigate the correlation between golfers’ subjective perceptions of the feel of a shot and the post-impact vibration of a club. Suitable test procedures were developed to quantify the golfers’ perceptions and to obtain measurements of vibration at the hands. The five feel characteristics investigated, ‘pleasantness’, ‘hardness’, ‘solidity’, ‘liveliness’ and perceived vibration level, were found to be strongly correlated; shots that were regarded as having a pleasant feel were also rated as having felt solid, lively, soft and with little vibration perceived. When these ratings were correlated with raw measurements of impact vibration, the relationships were initially weak. Techniques, such as normalizing the data, weighting the data and using mean data, were developed, resulting in much stronger correlations. Ultimately, a reduction in the total rms vibration level was found to correlate well with the players’ subjective descriptions of ‘pleasant’, ‘solid’, ‘lively’ and ‘soft’ feel

Evaluation of impact sound on the 'feel' of a golf shot

The ‘feel’ of a golf club is an important characteristic that has a significant influence on a golfer's choice of equipment. The sound from impact varies between different clubs and balls and this has been found to contribute to the feel of a shot. The aim of this study was to investigate the relationship between the impact sound and elite golfers’ subjective perceptions of the shot. Suitable test procedures were developed to quantify the golfers’ perceptions using a questionnaire and to measure the impact sound from the same shots. Statistical techniques were then employed to identify correlations between parameters of the impact sound and the golfers’ subjective ratings. The characteristics sharpness and loudness of sound and pleasantness and liveliness of feel were found to be strongly correlated; a shot was rated as having a pleasant feel if it had a loud, sharp sound and a lively feel. Strong positive correlations were also obtained between the subjective ratings and parameters of the impact sound such as sound pressure level, loudness level (according to ISO 532) and sharpness

Development and evaluation of new control algorithms for a mechanical golf swing device

Golf swing machines have become fundamental tools in the development of new equipment because they provide more consistent swing motions than golfers. Golf robots perform a simplification of the complex sequence of motions that compose a golf swing; however, traditional devices are typically capable of performing only a single swing profile at variable speeds. Significant differences exist between individual golfers’ swing motions, especially for golfers of different ability, experience, and physical stature, which suggests a requirement for swing profile variability in mechanical simulators. This investigation has found that the swing motion of a traditional golf robot provides a poor representation of golfers’ swings and, as a result, a bespoke control system has been developed for a commercially available golf robot to enable performance of variable swing profiles with positional feedback. Robot swing command files are generated by fitting a curve to a number of discrete data points that are equally spaced in time, and which define angles representative of individual golfers’ swings. The swing profiles of a professional golfer and a traditional golf robot were repeated accurately using this golf robot with a modified motion control system. The capability for individual golfers’ swings to be accurately replicated using a mechanical device was demonstrated using feedback data. All manufacturers recognize the importance of tailoring equipment to the unique characteristics of a particular golfer’s swing, and this increased robot functionality will provide considerable benefits in the development of customized equipment