Associations and Within-Group Differences in Physical Characteristics and Golf Performance Data in High-Level Amateur Players  
[PERSON]  
1 London Sport Institute, Middlesex University, London NW4 1 RL, UK; [EMAIL_ADDRESS] (A.B. ); [EMAIL_ADDRESS] (A.T.) Medical and Scientific Department, The R&A, St. Andrews KY16 9 JD, UK; [EMAIL_ADDRESS] (A.M.J. ); [EMAIL_ADDRESS] (D.C.) European Tour Health and Performance Institute, European Tour Group, Virginia Water GU25 4 LS, UK; [EMAIL_ADDRESS] (C.) Cambridge Centre for Sport & Exercise Sciences, Anglia Ruskin University, Cambridge CB1 1 PT, UK; [EMAIL_ADDRESS] (C.) Correspondence: [EMAIL_ADDRESS] (C.) (C.  
level, but they fail to highlight the more nuanced contribution of specific shot-related data. Consequently, launch monitor systems are now commonly used at the elite amateur and professional levels, and provide instantaneous feedback on a variety of shot-related metrics, such as clubhead speed (CHS), ball speed, carry distance, and more [3]. Although distance and dispersion (accuracy) are metrics that provide outcome measures for any given shot, independently, these metrics provide no context to how each shot is achieved. Therefore, launch monitors are useful in providing instantaneous data relating to the \"launch characteristics\" and \"impact factors\", which are able to help explain the outcome of a shot [3]. This has resulted in several studies investigating the associations between shot-related metrics and strength, explosive strength, and mobility or flexibility [4; 5; 6; 7]. The previous literature detailing the necessary physical capacities for golfers has suggested that strength and power (in both the lower and upper body) and mobility are the most important to develop and test [8; 9]. Specifically, previous studies have reported significant moderate associations between CHS and one repetition maximum squat (\(r=0.54\), \(p<0.05\)) [10] and peak force during an isometric mid-high pull (IMTP) (\(r=0.48\), \(p<0.05\)) [11]. Also, associations with upper body strength have been investigated with slightly weaker findings reported. For example, studies have shown significant moderate associations between CHS and one repetition maximum bench press (\(r=0.50\), \(p<0.05\)) [12] and lead hand grip strength (\(r=0.32\), non-significant) [13]. In terms of lower body power, previous studies have reported significant associations with CHS including countermovement (CMI)) positive impulse (\(r=0.70\)-\(0.79\), \(p<0.05\)) [4; 11] and peak power (\(r=0.61\), \(p<0.05\)) [10]. From an upper body power perspective, field-based testing has shown significant associations between CHS and rotational medicine ball throws (\(r=0.62\) and \(0.56\) for males and females, respectively, \(p<0.05\)) [5] and ball speed and ballistic bench press peak power (\(r=0.66\), \(p<0.05\)) [14]. Collectively then, it appears that moderate to large positive associations are evident between measures of lower and upper body strength and power and important golf performance measures such as CHS and ball speed. Despite this useful information, the majority of research has focused on outcome measures when it comes to physical characteristics (e.g., peak force, peak power, distance thrown, etc.). With the associations between these measures and CHS or ball speed rarely reported as being >0.7, a large amount of variance in physical capacity remains unaccounted for, justifying the need for a more comprehensive physical testing battery in golf. An additional physical characteristic which has a deep-routed history of perceived importance for golfers is flexibility. In support of this, a survey by [PERSON] and Langdown [15] reported \"flexibility and stretching\" to be the most common training modality employed by highly skilled golfers during the in-season period. The separation between the hips and thoracic spine is of importance to golfers, as this may contribute to large spikes in vertical ground reaction force before the downswing is initiated [16].