Timothy Exell

Dr. Timothy Exell


Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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27 September 2016 in Scandinavian Journal of Medicine & Science in Sports
Verified
Journal Article
Closed access
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TETimothy Exell
Timothy Exell
GIG. Irwin
G. Irwin
MGM. Gittoes
M. Gittoes
DKD. Kerwin
D. Kerwin

7 April 2020 in Journal of Sports Sciences
Verified
Journal Article
Closed access
ABAdam Brazil
Adam Brazil
TETimothy Exell
Timothy Exell
CWCassie Wilson
Cassie Wilson
Gareth IrwinGareth Irwin
Gareth Irwin
An essential component of any physical preparation programme is the selection of training exercises to facilitate desired performance outcomes, with practitioners balancing the principles of sports training to inform exercise selection. This study aimed to advance biomechanical understanding of the principles of overload and specificity within exercise selection, utilising novel joint kinetic and intra-limb joint coordination analyses. Three-dimensional kinematic and kinetic data were obtained from six male sprinters (100 m PB, 10.64–11.00) performing block starts (competitive motor task) and seven training exercises that encompassed traditionally viewed general and more specific exercises. Results highlighted the challenging nature of exercise selection, with all exercises demonstrating capacity to overload relevant joint kinetic features of the block start. In addition, all exercises were able to promote the emergence of proximal and in-phase extension joint coordination patterns linked with block start execution, although traditionally viewed non-specific exercises elicited greater overall coordination similarity. The current research helps advance biomechanical understanding of overload and specificity within exercise selection, by demonstrating how exercise selection should not solely be based on perceived replication of a competitive motor task. Instead, practitioners must consider how the musculoskeletal determinants of performance are overloaded, in addition to promoting task specific coordination patterns.

1 December 2015 in European Journal of Sport Science
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Journal Article
Closed access
TETimothy Exell
Timothy Exell
GRGemma Robinson
Gemma Robinson
GIGareth Irwin
Gareth Irwin
Asymmetry in gymnastics underpins successful performance and may also have implications as an injury mechanism; therefore, understanding of this concept could be useful for coaches and clinicians. The aim of this study was to examine kinematic and external kinetic asymmetry of the arm segments during the contact phase of a fundamental skill, the forward handspring on floor. Using a repeated single subject design six female National elite gymnasts (age: 19 ± 1.5 years, mass: 58.64 ± 3.72 kg, height: 1.62 ± 0.41 m), each performed 15 forward handsprings, synchronised 3D kinematic and kinetic data were collected. Asymmetry between the lead and non‐lead side arms was quantified during each trial. Significant kinetic asymmetry was observed for all gymnasts (p < 0.005) with the direction of the asymmetry being related to the lead leg. All gymnasts displayed kinetic asymmetry for ground reaction force. Kinematic asymmetry was present for more gymnasts at the shoulder than the distal joints. These findings provide useful information for coaching gymnastics skills, which may subjectively appear to be symmetrical. The observed asymmetry has both performance and injury implications.

26 July 2019 in International Journal of Performance Analysis in Sport
Verified
Journal Article
Closed access
JCJohan Cassirame
Johan Cassirame
HSH. Sanchez
H. Sanchez
TETimothy Exell
Timothy Exell
Vassilios PanoutsakopoulosVassilios Panoutsakopoulos
Vassilios Panoutsakopoulos
ATApostolos S. Theodorou
Apostolos S. Theodorou
JFJ. Frère
J. Frère
This study investigated biomechanical differences between successful and unsuccessful jumps during a pole vault competition. Two hundred and seven pairs of successful and unsuccessful jumps at the same height were analysed. Participants included male and female athletes of three different age groups with bar height clearances ranging from 2.81 to 5.91 m. Run-up parameters were collected using an Optojump Next system and a Stalker Pro II radar gun. A 2D kinematical analysis was conducted to obtain selected parameters of the take-off. Only trivial and small differences were found between successful and unsuccessful jumps. The speed at last touchdown showed a significant small difference between successful and unsuccessful jumps, as the greater speed at take-off (+0.15 m/s) was observed at successful jumps compared to unsuccessful jumps. Furthermore, female athletes showed a significant small difference in horizontal hand–foot distance between successful jumps and unsuccessful jumps (+0.05 m and +0.06 m at pole plant and take-off, respectively). The results suggest that pole vaulters should produce a fast run-up and avoid a decrease in speed before take-off. Small adjustments in the take-off posture might increase the transfer of energy from the athlete to the pole and thus an improvement concerning the height of bar clearance.

27 September 2021 in European Journal of Sport Science
Verified
Journal Article
Open access
RSRebecca Straker
Rebecca Straker
TETimothy Exell
Timothy Exell
RFRoman Farana
Roman Farana
JHJoseph Hamill
Joseph Hamill
Gareth IrwinGareth Irwin
Gareth Irwin
Inconsistencies between sexes in the landing criteria provided by the international gymnastics governing body (FIG) may predispose female gymnasts to lower extremity injury. This study aimed to investigate lower extremity biomechanics when performing the male and female landing strategy. Seven collegiate, female gymnasts (age: 20.5 ± 1.2 years, height: 1.64 ± 0.06 m, mass: 60.4 ± 10.2 kg) performed drop landings using the prescribed women's and men's landing strategy. Kinematic and kinetic data from 10 trials of each landing strategy were collected. Differences between landing strategy at individual and group level for key injury risk variables of the lower limb were explored. Group differences (p ≤ .05) were reported in the sagittal range of motion (ROM) at the knees and hips, with the men's landing strategy eliciting a larger ROM decelerating the body upon impact. Large inter and intra‐individual variation was apparent with different movement responses shown across individuals and demonstrating degeneracy as gymnasts satisfied the overall landing objective. These results indicate an individually favoured landing strategy to fulfil the informational constraints and hence supporting the use of a single‐subject design. The current study emphasises the potential injury risk associated with the different informational constraints placed on females’ landing strategy by the FIG, whilst recognising the individual gymnasts’ task response.Highlights An increase in the range of motion at the knee and hip may support the recommendation of the men's landing style. Gymnasts appear to utilise individual landing strategies to complete the landing objective, supporting the use of a single‐subject design.

1 January 2013 in Journal of Automatic Control
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Journal Article
Open access
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TETimothy Exell
Timothy Exell
CFChris Freeman
Chris Freeman
KMKatie L. Meadmore
Katie L. Meadmore
AHAnn-Marie Hughes
Ann-Marie Hughes
EHEmma Hallewell
Emma Hallewell
JBJane Burridge
Jane Burridge
Nonlinear optimisation-based search algorithms have been developed for the precise stimulation of muscles in the wrist and hand, to enable stroke patients to attain predefined gestures. These have been integrated in a system comprising a 40 element surface electrode array that is placed on the forearm, an electrogoniometer and data glove supplying position data from 16 joint angles, and custom signal generation and switching hardware to route the electrical stimulation to individual array elements. The technology will be integrated in a upper limb rehabilitation system currently undergoing clinical trials to increase their ability to perform functional tasks requiring fine hand and finger movement. Initial performance results from unimpaired subjects show the successful reproduction of six reference hand postures using the system.