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Dive into the research topics where John Hellström is active.

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Featured researches published by John Hellström.


Sports Medicine | 2009

Competitive elite golf a review of the relationships between playing results, technique and physique

John Hellström

Elite golfers commonly use fitness and technical training to become more competitive. The aim of this paper was to review the literature regarding the relationships between elite golfers’ playing results, technique and physique. The competitive outcome is a direct function of the score. The three golf statistical measures that show the strongest correlations to scoring average are greens in regulation (GIR), scrambling, and putts per GIR. However, more detailed game statistics are needed where the distances to the targets are known before and after the strokes. Players affect ball displacement by controlling clubhead velocity and clubface angle during club and ball impact. X-factor studies have produced ambiguous results, possibly caused by different definitions of upper torso, rotation and top of backswing. Higher clubhead speed is generally associated with larger spinal rotation and shoulder girdle protraction at the top of the backswing. It is also associated with higher ground reaction forces and torques, a bottom-up and sequential increase of body segment angular velocities, a rapid increase of spinal rotation and a late adduction of the wrists during the downswing. Players can increase the clubhead speed generated by a swinging motion by actively adding a force couple. Wrist, elbow and shoulder force couple strategies should be differentiated when investigating the technique. Physical parameters such as anthropometrics, strength and flexibility are associated with skill level and clubhead speed. Current studies have investigated the linear correlation between arm and shaft lengths and clubhead speed, but a quadratic relationship may be stronger due to changes in moment of inertia. Fitness training can increase and perhaps decrease the clubhead speed and striking distance, depending on training methods and the player’s fitness and level of skill. Future studies may focus on individual training needs and the relationship between physique, execution and its relation to accuracy of impact and ball displacement.


Sports Biomechanics | 2010

Elite golfers' kinematic sequence in full-swing and partial-swing shots

Fredrik Tinmark; John Hellström; Kjartan Halvorsen; Alf Thorstensson

The aim of this study was to investigate whether kinematic proximal-to-distal sequencing (PDS) and speed-summation are common characteristics of both partial and full-swing shots in golf players of different skill levels and genders. A total of 45 golfers participated, 11 male tournament professionals, 21 male and 13 female elite amateurs. They performed partial shots with a wedge to targets at three submaximal distances, 40, 55 and 70 m, and full-swing shots with a 5 iron and a driver for maximal distance. Pelvis, upper torso and hand movements were recorded in 3D with an electromagnetic tracking system (Polhemus Liberty) at 240 Hz and the magnitude of the resultant angular velocity vector of each segment was computed. The results showed a significant proximal-to-distal temporal relationship and a concomitant successive increase in maximum (peak) segment angular speed in every shot condition for both genders and levels of expertise. A proximal-to-distal utilization of interaction torques is indicated. Using a common PDS movement strategy in partial and full-swing golf shots appears beneficial from mechanical and control points of view and could serve the purpose of providing both high speed and accuracy.


Sports Medicine | 2009

Psychological hallmarks of skilled golfers

John Hellström

In this article, the psychological hallmarks of skilled golfers (professionals and amateurs with handicaps of ≤4) are investigated. Professional golfers believe that attitude, desire and motivation are important psychological qualities necessary to succeed in tournaments. They are committed to golf, have goals they strive for, make plans, evaluate their performance and systematically train towards improving their game. The study of skilled golfers’ traits, as measured by 16 personality factors, has provided ambiguous results and there may be more complex associations not yet investigated in golf.The effect of mood and emotions on golf scores seems to be individual. Differences in personality may explain why mood states, measured by mood state profiles, have not shown a strong correlation to golf scores. Task focus, confidence, imagery, patience, ability to focus on one shot at a time and performing automatically have been found to be important during competition. These variables need to be further researched before, during and after the swing. The psychological processes needed before, during and after the swing differ and should be further specified.A decrease in heart rate and a lower cortical activity moment before the swing may be signs of an optimal performance state. The effect of coping strategies may vary over time, and players should be able to switch and combine different strategies.Pre-shot routine is associated with performance. However, it is not clear if consistency of total duration and behavioural content in pre-shot routine cause improved performance. Pre-shot routine may also be an effect of psychological processes, such as a different task focus. It may facilitate an automatic execution of technique, which can lead to better performance. The psychological variables needed for competitive golf should be related to the physical, technical and game-statistical variables in coaching and future research.


International Journal of Sports Science & Coaching | 2008

The relation between physical tests, measures, and clubhead speed in elite golfers

John Hellström

The purpose of this study was to investigate the relationship between selected physical tests and clubhead speed, and whether body mass should be considered when presenting the test results. Thirty-three male elite golfers (estimated skill range: Hcp +5 to 0, age 18–30 years) participated in the study. The following test categories were measured and compared to clubhead speed with Pearson r correlation: vertical jumps (squat jump, counter movement jump, and counter movement jumps with arm swing); body mass strength (bar dips, pull-ups and vertical sit-ups); one repetition maximal strength (1-RM) (left grip, right grip and squat); and sprint (10 and 20 m). The tests and measures significantly (p < 0.05) related to clubhead speed were body mass, all vertical jumps (peak power and jump height), sprint (mean power), right grip (mass), squat (mass), bar dips (repetitions x body mass), and vertical sit-ups (repetitions x body mass). These tests may be selected when players and coaches wish to analyse physical test results associated to clubhead speed. Peak power in vertical jumps is more strongly related to clubhead speed than jump height, but jump height may be used too. In sprint, mean power should be used for feedback instead of sprint time. Strength test results should be presented in absolute values (kg), not as relative strength. Body mass should be considered in vertical jumps, sprints, and body mass strength tests, but not in 1RM strength tests with external resistance.


Journal of Sports Sciences | 2014

Drive for dough. PGA Tour golfers’ tee shot functional accuracy, distance and hole score

John Hellström; Johnny Nilsson; Leif Isberg

Abstract A player’s ability to score low is critical to the tournament outcome in golf. The relationships of round scores to fairways hit in regulation or striking distance on two holes per round have been investigated before with some disagreement. The purpose is therefore to examine the relationships of par-4 and par-5 hole scores to tee shot functional accuracy and distance, measured as lie of the ball and penalty, and striking distance or distance to the pin for the second shot. Such information is possible to collect without interviewing players. The best US Professional Golfers’ Association Tour players’ statistics during a season are used, provided by the Professional Golfers’ Association Tour and ShotLink. Distance was measured with laser equipment. The results include significant (P < 0.05) correlations between score and striking distance or distance to pin, when hitting rough but not fairway on par-4s and when hitting fairway and rough on par-5s. It is therefore relevant, for performance, to consider the type of fairway miss as well as the striking distance in relation to the par and length of the hole. The findings can be considered when making gap and needs profiles, and when making tactical decisions for tee shots on different types of holes.


ISBS 27th International Conference on Biomechanics in Sports. Limerick, Ireland. August 17 – 21, 2009 | 2009

ANALYSIS OF ELITE GOLFERS’ KINEMATIC SEQUENCE IN FULL-SWING AND PARTIAL SWING SHOTS

Fredrik Tinmark; John Hellström; Kjartan Halvorsen; Alf Thorstensson


Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology | 2018

The effect of ball temperature on ball speed and carry distance in golf drives

Magnus Carlsson; Johnny Nilsson; John Hellström; Fredrik Tinmark; Tomas Carlsson


International Society of Biomechanics Conference, ISB 2015. Glasgow, July 12-16 2015. | 2015

Endpoint mobility in bimanual manipulation: insights from golf ball striking

Fredrik Tinmark; Anton Arndt; Maria Ekblom; John Hellström; Kjartan Halvorsen


Archive | 2014

Endpoint control in a bimanual striking task : application to the golfswing

Fredrik Tinmark; Toni Ardt; Maria Ekblom; John Hellström; Kjartan Halvorsen


The 30th Conference of the International Society of Biomechanics in Sports, Melbourne, Australia, July 02 – July 06, 2012 | 2012

Contributions to club velocity in golf swings to submaximal and maximal shot distances

Fredrik Tinmark; John Hellström; Anton Arndt; Kjartan Halvorsen

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Johnny Nilsson

Norwegian School of Sport Sciences

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Fredrik Tinmark

Gymnastik- och idrottshögskolan

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Kjartan Halvorsen

Gymnastik- och idrottshögskolan

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