Fredrik Tinmark | GIH - Academia.edu (original) (raw)

Papers by Fredrik Tinmark

Journal of strength and conditioning research, Apr 11, 2024

Journal of Biomechanics, Dec 31, 2023

Proceedings Of The Institution Of Mechanical Engineers, Part P: Journal Of Sports Engineering And Technology, Nov 28, 2018

The purpose of this study was to investigate the effect of ball temperature on impact ball speed ... more The purpose of this study was to investigate the effect of ball temperature on impact ball speed and carry distance during golf drives in a blind randomized test design. The balls were exposed to a temperature-controlled environment (4°C, 18°C, 32°C, and 46°C) for 24 h prior to the test and each temperature group consisted of 30 balls. The 120 drives were performed by an elite male golfer (handicap: 0.0) in an indoor driving range. All drives were measured by a Doppler-radar system to determine the club-head speed, launch angle, spin rate, ball speed, and carry distance. Differences between the groups were investigated using a one-way analysis of variance. The results indicated that ballspeed and carry-distance differences occurred within the four groups (p \ 0.001 and p \ 0.01, respectively). The post hoc analyses showed that the ball temperatures of 18°C and 32°C had greater ball speeds and carry distances than balls at 4°C and 46°C (all p \ 0.05). The intervals for the between-group differences were 0.6-0.7 m s 21 and 2.9-3.9 m for ball speed and carry distance, respectively. Hence, the results showed that ball temperature influences both the ball speed and the carry distance. Based on the findings in this study, standardization of ball temperature should be factored into governing body regulation tests for golf equipment.

Step-Length Changes Caused by a Dual-Task Test among Individuals Undergoing Memory Assessment – A... more Step-Length Changes Caused by a Dual-Task Test among Individuals Undergoing Memory Assessment – A Pilot Study

Medicine & Science in Sports & Exercise

Trunk curls are common exercises in sports training. A multitude of practical recommendations exi... more Trunk curls are common exercises in sports training. A multitude of practical recommendations exist on how to best perform this type of exercise to reach a specific effect. Since abdominal muscles can contribute to breathing, it was thought of interest to study the effects of systematic variations in breathing on the pattern of abdominal muscle activation during trunk curls. Of particular interest was the influence of fluctuations in the intra-abdominal pressure (IAP), since changes in IAP have been shown to be coupled to the activation of the innermost abdominal muscle, the Transversus abdominis (TrA), and also to be able to contribute to an extensor moment of the trunk.

International Journal of Environmental Research and Public Health, 2020

New methods to screen for and identify early-stage dementia disorders are highly sought after. Th... more New methods to screen for and identify early-stage dementia disorders are highly sought after. The purpose of this pilot study is to develop a study protocol for a dual-task test aimed at aiding the early detection of dementia disorders. We used the Timed Up-and-Go (TUG) test, which is a mobility task involving starting in a sitting position, standing up, walking three meters to cross a line on the floor, turning around, walking back and sitting down again. We combined TUG with the verbal task of naming different animals. Pilot study participants were 43 individuals with and without established dementia diagnoses who attended a clinic for memory assessment. Video-recorded test performances were systematically analysed. Deviant test performances concerning the interplay between test administration and participants’ responses to the assessment instructions were revealed and led to refinements being made to the final study protocol. Exploration of the dual-task test outcome measures in...

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

The purpose of this study was to investigate the effect of ball temperature on impact ball speed ... more The purpose of this study was to investigate the effect of ball temperature on impact ball speed and carry distance during golf drives in a blind randomized test design. The balls were exposed to a temperature-controlled environment (4 °C, 18 °C, 32 °C, and 46 °C) for 24 h prior to the test and each temperature group consisted of 30 balls. The 120 drives were performed by an elite male golfer (handicap: 0.0) in an indoor driving range. All drives were measured by a Doppler-radar system to determine the club-head speed, launch angle, spin rate, ball speed, and carry distance. Differences between the groups were investigated using a one-way analysis of variance. The results indicated that ball-speed and carry-distance differences occurred within the four groups ( p < 0.001 and p < 0.01, respectively). The post hoc analyses showed that the ball temperatures of 18 °C and 32 °C had greater ball speeds and carry distances than balls at 4 °C and 46 °C (all p < 0.05). The intervals...

Using Motion Analysis and Pressure sensitive sensors for determining normal forces when gripping ... more Using Motion Analysis and Pressure sensitive sensors for determining normal forces when gripping a cylinder

The contribution of joint rotations to endpoint velocity was investigated in golf shots to submax... more The contribution of joint rotations to endpoint velocity was investigated in golf shots to submaximal and maximal shot distances using a 41degrees of freedom (DOF) kinematic model. A subset of 16 DOFs was found to explain 97%-99% of endpoint velocity regulation at club-ball contact. The largest contributors, for both groups at every shot condition, were pelvis and torso twist rotation among the most proximal DOFs, elbow pronation/supination and wrist flexion/extension among DOFs in the left arm, and shoulder internal/external rotation and wrist flexion/extension among DOFs in the right arm. The contributions from pelvis obliquity, left wrist flexion/extension, left wrist ulnar/radial deviation and right shoulder flexion/extension differed significantly between the advanced and intermediate group.

The aim of this thesis was to gain insight into the control of complex bimanual movements that ar... more The aim of this thesis was to gain insight into the control of complex bimanual movements that are both fast and accurate. For this, skilled golf ball striking was used as a model in two experimental studies (I and III). The thesis also includes two methodological studies (II and IV), intended to assist in present and future investigation on bimanual movement control. Study I shows a common kinematic proximal-to-distal sequencing (PDS) pattern and speed-summation effect in skilled golf players of both genders. Using a common PDS movement strategy in golf ball striking at various endpoint speeds appears beneficial from mechanical and control points of view and could serve the purpose of providing both high speed and accuracy. In Study II a general expression for mobility was derived, which can be applied for extending the theory of mobility to double-handed grasping and manipulation. Study III found that kinematic contributions to endpoint velocity at slow, medium and fast test conditions were provided by the same subset of possible joint rotations. However, the specific subset differed between levels of expertise. The inertial behavior of the linkage arms-hands-club promoted movement parallel to and resisted movement orthogonal to the club path close to ball impact, at all endpoint speeds investigated. These findings extend previous knowledge regarding endpoint control in single-limb movements. Moreover, results regarding movement organization in Study I together with results in Study III regarding inertial behavior suggest the existence of limb configurations able to simultaneously exploit intersegmental dynamics and endpoint mobility in a proficient manner. To make the control of intersegmental dynamics in bimanual striking transparent, however, torques originating from segmental in teractions should be determined. However, when hands are placed next to each other or are overlapping it becomes challenging to find placements for standard force sensors which allow separation of right and left hand forces without altering normal behavior. As partially explored in Study IV, pressure mapping of the right hand together with inverse dynamics calculations for the golf club can potentially provide an adequate solution.

This study aimed to evaluate biomechanics during seated double-poling exercises in individuals wi... more This study aimed to evaluate biomechanics during seated double-poling exercises in individuals with spinal cord injury (SCI) and to compare these with those of able-bodied persons (AB). 26 participants volunteered for the study; 13 with SCI (injury levels C7-T12), and 13 AB. A seated double-poling ergometer (SDPE) was developed. 3-dimensional kinematics was measured and piezoelectric force sensors were used to register force in both poles for calculation of power during incremental intensities. Significantly lower power outputs, (143.2 ± 51.1 vs. 198.3 ± 74.9 W) and pole forces (137.1 ± 43.1 vs. 238.2 ± 81.2 N) were observed during maximal effort in SCI compared to AB. Sagittal upper trunk range of motion increased with intensity and ranged from 6.1-34.8° for SCI, and 6.9-31.3° for AB, with larger peak amplitudes in flexion for AB (31.4 ± 12.9°) compared to SCI (10.0 ± 8.0°). All subjects with SCI were able to exercise on the SDPE. Upper body kinematics, power and force outputs increased with intensity in both groups, but were in general, lower in SCI. In conclusion, the SDPE could be successfully used at low to high work intensities enabling both endurance and strength training for individuals with SCI.

Proceedings of ISB …, 2011

The contribution of joint rotations to endpoint velocity was investigated in golf shots to submax... more The contribution of joint rotations to endpoint velocity was investigated in golf shots to submaximal and maximal shot distances using a 41degrees of freedom (DOF) kinematic model. A subset of 18 DOFs could explain 92% to 98% of endpoint velocity at club-ball contact. The percentage contributions of left shoulder abduction, left wrist extension and right shoulder internal rotation to endpoint velocity differed significantly between test conditions. These differences may reflect task-specific alterations that are beneficial for attaining different task goals. For the remaining 15 DOFs, no significant differences between test conditions were detected. As a possible consequence of the two-handed grip and the mechanical coupling of the arms, right elbow extension showed negative contributions at impact. This contrasts to findings in single-limb tasks such as the overarm throw and the tennis serve, where right elbow extension is a major contributor to endpoint velocity at ball release/impact.

… of ECSS 16th …, 2011

... reference ». Author: Halvorsen, Kjartan (KTH, School of Technology and Health (STH), Medical ... more ... reference ». Author: Halvorsen, Kjartan (KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS)). Eriksson, Martin (KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS)). Nilsson, Johnny (The Swedish ...

Sports Biomechanics, 2010

The purposes of the present study were, to determine if partial and full-swing shots performed by... more The purposes of the present study were, to determine if partial and full-swing shots performed by skilled golfers were organized in a proximal-to-distal sequencing (PDS) pattern and to examine the speed-summation effect at pelvis, upper torso and hand segments. Method Three-dimensional kinematic recordings of pelvis, upper torso, and hand were made while forty-seven skilled golfers stroke three different clubs a range of submaximal and maximal shot distances. Results This study showed a clear proximal-to-distal temporal relationship of movement onset and peak angular speed at the pelvis, upper torso and hand segments in the golf swing. The same temporal structure was evident at all test conditions, among different gender and level of expertise. Further, results revealed a summation effect of angular velocity from proximal-todistal, with each succeeding segment generating a larger rotational speed than the proximal segment. However, the increment in speed from proximal-to-distal was different among gender and level of expertise. Conclusions The temporal relation of segment kinematics suggests a common PDS organization in partial and full-swing shots for skilled golfers. A speed-summation effect of segmental angular speed indicates that participants did utilize interaction torques in a proximal-to-distal manner. The role of the observed PDS organization and speed-summation effect in partial shots might be to improve accuracy and, potentially, golfers should concentrate on speed initially in learning the golf swing.

Gait & Posture, 2009

Fourteen male subjects (22 AE 2 years, 180 AE 6 cm, 71 AE 8 kg) representing orienteering, middle... more Fourteen male subjects (22 AE 2 years, 180 AE 6 cm, 71 AE 8 kg) representing orienteering, middle-and long distance running and football participated in the study. Each subject was comfortable with tredmill-running at speeds up to 22 km h À1. The subjects gave written consent. The study was approved by the regional ethical review board, and performed according to the Helsinki declaration. 2.2. Instrumentation An optoelectronic 3D motion analysis system with eight infrared cameras

Journal of strength and conditioning research, Apr 11, 2024

Journal of Biomechanics, Dec 31, 2023

Proceedings Of The Institution Of Mechanical Engineers, Part P: Journal Of Sports Engineering And Technology, Nov 28, 2018

Medicine & Science in Sports & Exercise

International Journal of Environmental Research and Public Health, 2020

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

The purpose of this study was to investigate the effect of ball temperature on impact ball speed ... more The purpose of this study was to investigate the effect of ball temperature on impact ball speed and carry distance during golf drives in a blind randomized test design. The balls were exposed to a temperature-controlled environment (4 °C, 18 °C, 32 °C, and 46 °C) for 24 h prior to the test and each temperature group consisted of 30 balls. The 120 drives were performed by an elite male golfer (handicap: 0.0) in an indoor driving range. All drives were measured by a Doppler-radar system to determine the club-head speed, launch angle, spin rate, ball speed, and carry distance. Differences between the groups were investigated using a one-way analysis of variance. The results indicated that ball-speed and carry-distance differences occurred within the four groups ( p < 0.001 and p < 0.01, respectively). The post hoc analyses showed that the ball temperatures of 18 °C and 32 °C had greater ball speeds and carry distances than balls at 4 °C and 46 °C (all p < 0.05). The intervals...

Proceedings of ISB …, 2011

The contribution of joint rotations to endpoint velocity was investigated in golf shots to submax... more The contribution of joint rotations to endpoint velocity was investigated in golf shots to submaximal and maximal shot distances using a 41degrees of freedom (DOF) kinematic model. A subset of 18 DOFs could explain 92% to 98% of endpoint velocity at club-ball contact. The percentage contributions of left shoulder abduction, left wrist extension and right shoulder internal rotation to endpoint velocity differed significantly between test conditions. These differences may reflect task-specific alterations that are beneficial for attaining different task goals. For the remaining 15 DOFs, no significant differences between test conditions were detected. As a possible consequence of the two-handed grip and the mechanical coupling of the arms, right elbow extension showed negative contributions at impact. This contrasts to findings in single-limb tasks such as the overarm throw and the tennis serve, where right elbow extension is a major contributor to endpoint velocity at ball release/impact.

… of ECSS 16th …, 2011

Sports Biomechanics, 2010

Gait & Posture, 2009