Does lateral banking and radius affect well-trained sprinters and team-sports players during bend sprinting?

This study investigated the short-term responses of step characteristics in sprinters and team-sports players under different bend conditions. Eight participants from each group completed 80 m sprints in four conditions: banked and flat, in lanes two and four (L2B, L4B, L2F, L4F). Groups showed similar changes in step velocity (SV) across conditions and limbs. However, sprinters produced significantly shorter ground contact times (GCT) than team sports players in L2B and L4B for both left (0.123 s vs 0.145 s and 0.123 s vs 0.140 s) and right steps (0.115 s vs 0.136 s and 0.120 s vs 0.141 s) (p > 0.001-0.029; ES = 1.15-1.37). Across both groups, SV was generally lower in flat conditions compared to banked (Left: 7.21 m/s vs 6.82 m/s and Right: 7.31 m/s vs 7.09 m/s in lane two), occurring due to reduced step length (SL) rather than step frequency (SF), suggesting that banking improves SV via increased SL. Sprinters produced significantly shorter GCT in banked conditions that led to non-significant increases in SF and SV, highlighting the importance of bend sprinting specific conditioning and training environments representative of indoor competition for sprint athletes.

Task Specific and General Patterns of Joint Motion Variability in Upright- and Hand-Standing Postures.

The preservation of static balance in both upright- and hand-stance is maintained by the projection of center of mass (CM) motion within the region of stability at the respective base of support. This study investigated, from a degrees of freedom (DF) perspective, whether the stability of the CM in both upright- and hand-stances was predicted by the respective dispersion and time-dependent regularity of joint (upright stance-ankle, knee, hip, shoulder, neck; hand stance-wrist, elbow, shoulder, neck) angle and position. Full body three-dimensional (3D) kinematic data were collected on 10 advanced level junior female gymnasts during 30 s floor upright- and hand-stands. For both stances the amount of the dispersion of joint angle and sway motion was higher than that of the CM and center of pressure (CP) with an inverse relation to time-dependent irregularity (SampEn). In upright-standing the variability of neck motion in the anterior-posterior direction was significantly greater than that of most joints consistent with the role of vision in the control of quiet upright posture. The findings support the proposition that there are both task specific and general properties to the global CM control strategy in the balance of upright- and hand-standing induced by the different active skeletal-muscular organization and the degeneracy revealed in the multiple distributional variability patterns of the joint angle and position in 3D.

A biomechanical approach to evaluate overload and specificity characteristics within physical preparation exercises.

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.

Joint kinetic determinants of starting block performance in athletic sprinting.

The aim of this study was to explore the relationships between lower limb joint kinetics, external force production and starting block performance (normalised average horizontal power, NAHP). Seventeen male sprinters (100 m PB, 10.67 ± 0.32 s) performed maximal block starts from instrumented starting blocks (1000 Hz) whilst 3D kinematics (250 Hz) were also recorded during the block phase. Ankle, knee and hip resultant joint moment and power were calculated at the rear and front leg using inverse dynamics. Average horizontal force applied to the front (r = 0.46) and rear (r = 0.44) block explained 86% of the variance in NAHP. At the joint level, many "very likely" to "almost certain" relationships (r = 0.57 to 0.83) were found between joint kinetic data and the magnitude of horizontal force applied to each block although stepwise multiple regression revealed that 55% of the variance in NAHP was accounted for by rear ankle moment, front hip moment and front knee power. The current study provides novel insight into starting block performance and the relationships between lower limb joint kinetic and external kinetic data that can help inform physical and technical training practices for this skill.

The Effect of Clinical Pilates on Functional Movement in Recreational Runners.

Biomechanical imbalances and inefficient functional movements are considered contributing factors to running-related injuries. Clinical Pilates uses a series of exercises focused on retraining normal movement patterns. This study investigated whether a 6-week course of Clinical Pilates improves functional movement and thereby, potentially, reduces the risk of running-related injuries associated with movement dysfunction. A modified functional movement screen was used to analyze the functional movement ability of forty runners. Forty participants completed a 6-week course of Clinical Pilates delivered by a Clinical Pilates instructor. The movement screen was carried out 3 times for each runner: 6 weeks pre-intervention (baseline), within one week pre-intervention (pre) and within one week post-intervention (post). Repeated-measures analysis of variance and post-hoc tests found significant increases in scores between baseline and post (mean±SD; 13.4±2.4 vs. 17.0±1.7, p<0.01) and pre and post (mean±SD; 13.5±2.5 vs. 17.0±1.7, p<0.01), but no significant difference between baseline and pre (p=0.3). A 6-week course of Clinical Pilates significantly improves functional movement in recreational runners, and this may lead to a reduction in the risk of running-related injuries.

Lower limb joint kinetics in the starting blocks and first stance in athletic sprinting.

The aim of this study was to examine lower limb joint kinetics during the block and first stance phases in athletic sprinting. Ten male sprinters (100 m PB, 10.50 ± 0.27 s) performed maximal sprint starts from blocks. External force (1000 Hz) and three-dimensional kinematics (250 Hz) were recorded in both the block (utilising instrumented starting blocks) and subsequent first stance phases. Ankle, knee and hip resultant joint moment, power and work were calculated at the rear and front leg during the block phase and during first stance using inverse dynamics. Significantly (P < 0.05) greater peak moment, power and work were evident at the knee joint in the front block and during stance compared with the rear block. Ankle joint kinetic data significantly increased during stance compared with the front and rear block. The hip joint dominated leg extensor energy generation in the block phase (rear leg, 61 ± 10%; front leg, 64 ± 8%) but significantly reduced during stance (32 ± 9%), where the ankle contributed most (42 ± 6%). The current study provides novel insight into sprint start biomechanics and the contribution of the lower limb joints towards leg extensor energy generation.

Movement variability and skills monitoring in sports.

The aim of this paper was to present a review on the role that movement variability (MV) plays in the analysis of sports movement and in the monitoring of the athlete's skills. MV has been traditionally considered an unwanted noise to be reduced, but recent studies have re-evaluated its role and have tried to understand whether it may contain important information about the neuro-musculo-skeletal organisation. Issues concerning both views of MV, different approaches for analysing it and future perspectives are discussed. Information regarding the nature of the MV is vital in the analysis of sports movements/motor skills, and the way in which these movements are analysed and the MV subsequently quantified is dependent on the movement in question and the issues the researcher is trying to address. In dealing with a number of issues regarding MV, this paper has also raised a number of questions which are still to be addressed.

Intra-limb coordinative adaptations in cycling.

This study aimed to establish the nature of lower extremity intra-limb coordination variability in cycling and to investigate the coordinative adaptations that occur in response to changes in cadence and work rate. Six trained and six untrained males performed nine pedalling bouts on a cycle ergometer at various cadences and work rates (60, 90, and 120 revolutions per minute (rpm) at 120, 210, and 300W). Three-dimensional kinematic data were collected and flexion/extension angles of the ankle, knee, and hip joints were subsequently calculated. These data were used to determine two intra-limb joint couplings [hip flexion/extension-knee flexion/extension (HK) and knee flexion/extension-ankle plantar-flexion/dorsi-flexion (KA)], which were analysed using continuous relative phase analysis. Trained participants displayed significantly (p < 0.05) lower coordination variability (6.6 +/- 4.0 degrees) than untrained participants (9.2 +/- 4.7 degrees). For the trained subjects, the KA coupling displayed significantly more in-phase motion in the 120 rpm (19.2 +/- 12.3 degrees) than the 60 (30 +/- 7.1 degrees) or 90 rpm (33.1 +/- 7.4 degrees) trials and the HK coupling displayed significantly more in-phase motion in the 90 (33.3 +/- 3.4 degrees) and 120 rpm (27.9 +/- 13.6 degrees) than in the 60 rpm trial (36.4 +/- 3.5 degrees). The results of this study suggest that variability may be detrimental to performance and that a higher cadence is beneficial. However, further study of on-road cycling is necessary before any recommendations can be made.

Angular dynamics in vector coding: a new approach based on angular velocity.

The assessment of coordination variability in multi-joint human movements has traditionally started from angle-angle representations, and then used the angle change between subsequent time points as input for further analysis through vector coding. We propose an improvement to this approach, and suggest employing angular velocities as input data (Velocity Ellipse Method, VEM). We used experimental data and theoretical principles to contrast VEM with an existing standard (Difference Ellipse Method) and discuss its advantages and potential issues. Normalised cross-correlation was used to compare VEM and DEM in 36 angle couplings, from 20 participants running at 12 km/h on a treadmill. The hip flexion/extension-knee flexion/extension data were further investigated to discuss the robustness of the approach to measurement noise and outliers. Although DEM and VEM generally exhibited similar patterns (cross-correlation between 0.851 and 0.999), the variability curves from the two methods were noticeably different in some intervals. Also, using angular velocities as input appeared more robust to potential noise from raw data whilst retaining the following features: (a) more coherent with biomechanical conventions for calculating three-dimensional angular dynamics; (b) still suitable for coordination analysis; and, (c) more easily interpretable by practitioners when represented as relative motion plots.

"We are not hard to reach, but we may find it hard to trust" . Involving and engaging 'seldom listened to' community voices in clinical translational health research: a social innovation approach.

BACKGROUND: Public involvement in clinical translational research is increasingly recognised as essential for relevant and reliable research. Public involvement must be diverse and inclusive to enable research that has the potential to reach those that stand to benefit from it the most, and thus address issues of health equity. Several recent reports, however, indicate that public involvement is exclusive, including in its interactions with ethnic groups. This paper outlines a novel community-led methodology - a community sandpit - to address the inclusion of ethnic groups in public involvement in research, reports on its evaluation, findings, legacy and impact. METHODS: Through detailed planning - thinking through and taking into account all stakeholders perspectives in the planning and design of the sandpit, relationship-building, co-design and co-delivery between the Public Programmes team based at Manchester University NHS Foundation Trust and the Greater Manchester Black and Minority Ethnic Network - the community sandpit was held in July 2018. RESULTS: Fifteen community organisations took part in the two-day event, as well as six researchers, and six creative practitioners. Six community-based partnership projects were seed-funded; four of these received additional funding from other sources also. CONCLUSIONS: Evaluation of the sandpit showed the format to be well-received by all: it levelled power relationships between community organisations, health researchers and research infrastructure; it developed capacity amongst researchers about the accessibility, role and potential of community organisations. Described as "not another community seed fund" by community partners, the sandpit offered community partners, equitable avenues for collaboration within Greater Manchester translational research and led to the formation of the Black, Asian and Minority Ethnic Research Advisory Group (BRAG Vocal Website information, - https://www.wearevocal.org/opportunities/black-asian-and-minority-ethnic-research-advisory-group-brag/ , 2021). The method has the potential to be replicated elsewhere to support inclusive public involvement in research and inclusive research.

Public involvement in "bench to bedside" research (from laboratory-based research to clinical practice) is increasingly recognised as essential for relevant and reliable research. To enable the findings from health research to meet the needs of those who stand to benefit from it the most and to ensure that differences in health and disease are reduced as much as possible, public involvement must be diverse and inclusive. Recent reports, however, indicate that public involvement is exclusive, including in its interactions with racially minoritised groups. This paper outlines a novel community-led methodology ­ a community sandpit ­ to address the inclusion of ethnic groups in public involvement in research, reports on its evaluation, findings, legacy and impact.Through detailed planning ­ thinking through and taking into account all stakeholders perspectives in the planning and design of the sandpit, relationship-building, co-design and co-delivery between the Public Programmes Team (now Vocal) based at Manchester University NHS Foundation Trust worked with the Greater Manchester Black and Minority Ethnic Network - the community sandpit was held in July 2018. Fifteen community organisations took part in the two-day event, as well as six researchers, and six creative practitioners (artists with experience of working with the public on socially engaged projects to engage them in areas such as science). Six community-based partnership projects were seed-funded; four of these received additional funding from other sources. Evaluation of the sandpit showed the format to be well-received by all: it levelled power relationships between community organisations, health researchers and research infrastructure; it increased researchers knowledge and insights about the accessibility of community organisations and of how they might work effectively with them. Described as "not another community seed fund" by community partners, the sandpit began the process of levelling the playing field for collaboration between Greater Manchester translational research and local community organisations and led to the formation of the Black, Asian and Minority Ethnic Research Advisory Group (BRAG) (Vocal Website information, - https://www.wearevocal.org/opportunities/black-asian-and-minority-ethnic-research-advisory-group-brag/ , 2021). The method has the potential to be repeated elsewhere to support inclusive public involvement in research and inclusive research.

A biomechanical comparison of initial sprint acceleration performance and technique in an elite athlete with cerebral palsy and able-bodied sprinters.

Cerebral palsy is known to generally limit range of motion and force producing capability during movement. It also limits sprint performance, but the exact mechanisms underpinning this are not well known. One elite male T36 multiple-Paralympic sprint medallist (T36) and 16 well-trained able-bodied (AB) sprinters each performed 5-6 maximal sprints from starting blocks. Whole-body kinematics (250 Hz) in the block phase and first two steps, and synchronised external forces (1,000 Hz) in the first stance phase after block exit were combined to quantify lower limb joint kinetics. Sprint performance (normalised average horizontal external power in the first stance after block exit) was lower in T36 compared to AB. T36 had lower extensor range of motion and peak extensor angular velocity at all lower limb joints in the first stance after block exit. Positive work produced at the knee and hip joints in the first stance was lower in T36 than AB, and the ratio of positive:negative ankle work produced was lower in T36 than AB. These novel results directly demonstrate the manner in which cerebral palsy limits performance in a competition-specific sprint acceleration movement, thereby improving understanding of the factors that may limit performance in elite sprinters with cerebral palsy.

Determinants of time to fatigue during nonmotorized treadmill exercise.

Treadmill exercise is commonly used for aerobic and anaerobic conditioning. During nonmotorized treadmill exercise, the subject must provide the power necessary to drive the treadmill belt. The purpose of this study was to determine what factors affected the time to fatigue on a pair of nonmotorized treadmills. Twenty subjects (10 men/10 women) attempted to complete 5 minutes of locomotion during separate trials at 3.22, 4.83, 6.44, 8.05, 9.66, and 11.27 kmxh. Total exercise time (

Innovating public engagement and patient involvement through strategic collaboration and practice.

BACKGROUND: Patient and public involvement and engagement is an important and expected component of health-related research activity in the UK. Specifically within the health research sphere, public engagement (usually defined as raising awareness of research) and patient involvement (usually defined as actively involving people in research) have traditionally been seen as separate but have much to gain from working together towards a common goal of better health outcomes for all. METHODS: This paper describes a unique approach taken by the Public Programmes Team: a small interdisciplinary team of public engagement specialists, with backgrounds in science, community development, public engagement and involvement, policy, ethics, communications, industry, museums and creative practice, embedded within translational research infrastructure and delivery in Manchester in the North West of England. We propose a new model of professional practice - a 'cycle' of engagement and involvement - innovating across the complementary fields of public engagement and patient involvement, and working inclusively and in partnership with people in health research. Further, our approach capitalises on strategic collaboration offering economies of scale and a joined up way of working. Our ambition is to boldly experiment, learn and reflect, responsibly and based on evidence and partnerships, using methods of engagement that address issues of social justice. RESULTS: Here, we report on preliminary case studies exemplifying the impact of our approach, and data relating to achievements and learning between April 2017 and March 2018. Informed by our findings, we propose that our approach has the potential to be replicated elsewhere. CONCLUSIONS: Our practice and the beginning of its evaluation lead us to believe that our way of working and model of professional practice - the 'cycle' of engagement and involvement - is effective in: addressing our vision of making health research relevant and inclusive for everyone; and embedding and joining up public involvement in a busy and fertile translational health research ecosystem.

Noninvasive determination of exercise-induced hydrodgen ion threshold through direct optical measurement.

The intensity of exercise above which oxygen uptake (Vo2) does not account for all of the required energy to perform work has been associated with lactate accumulation in the blood (lactate threshold, LT) and elevated carbon dioxide output (gas exchange threshold). An increase in hydrogen ion concentration ([H+]) is approximately concurrent with elevation of blood lactate and CO2 output during exercise. Near-infrared spectra (NIRS) and invasive interstitial fluid pH (pHm) were measured in the flexor digitorum profundus during handgrip exercise to produce a mathematical model relating the two measures with an estimated error of 0.035 pH units. This NIRS pHm model was subsequently applied to spectra collected from the vastus lateralis of 10 subjects performing an incremental-intensity cycle protocol. Muscle oxygen saturation (SmO2) was also calculated from spectra. We hypothesized that a H+ threshold could be identified for these subjects and that it would be different from but correlated with the LT. Lactate, gas exchange, SmO2, and H+ thresholds were determined as a function of Vo2 using bilinear regression. LT was significantly different from both the gas exchange threshold (Delta = 0.27 +/- 0.29 l/min) and H+ threshold (Delta = 0.29 +/- 0.23 l/min), but the gas exchange threshold was not significantly different from the H+ threshold (Delta = 0.00 +/- 0.38 l/min). The H+ threshold was strongly correlated with LT (R2 = 0.95) and the gas exchange threshold (R2 = 0.85). This initial study demonstrates the feasibility of noninvasive pHm estimations, the determination of H+ threshold, and the relationship between H+ and classical metabolic thresholds during incremental exercise.

Coordination variability and skill development in expert triple jumpers.

The aim of this study was to examine the influence of skill of expert triple jumpers on the coordination variability of lower extremity intra-limb couplings. In contrast to the traditional motor learning perspective, we hypothesized that as skill and thus performance increases, movement coordination variability will also increase. Three-dimensional kinematic and ground reaction force data were collected during the hop-step transition phase of the triple jump. Relative motion plots and a modified vector coding technique were used to quantify the coordination variability across the trials. The results were consistent with a U-shaped curve, representing coordination variability, as skill increases. The high coordination variability in less skilled athletes is present while the appropriate characteristics defining the movement coordination patterns are acquired. This coordination variability may not be beneficial to performance. As the refinement of these characteristics is achieved, coordination variability decreases, resulting in a more consistent or regulated performance. In the final stages of developing a skilled performance, a functional variability is accessed that brings flexibility to the system allowing it to cope with perturbations. This study highlights the need to address the learning effect when analysing coordination variability from a dynamical systems perspective.

Applying circular statistics can cause artefacts in the calculation of vector coding variability: A bivariate solution.

BACKGROUND: Coordination variability is thought to provide meaningful insights into motor learning, skill level and injury prevention. Current analytical techniques, based on vector coding (VC) methods, use calculations from circular statistics. However a statistical artefact associated with the application of circular statistics may artificially increase the estimated coordination variability, especially when VC vectors are short. RESEARCH QUESTION: Are two popular methods for calculating vector coding coordination variability susceptible to contamination by statistical artefacts and if so, how can coordination variability be calculated without statistical artefact? METHODS: A combination of simulated and experimental data was used to prove the existence of the statistical artefact and to understand the extent to which it may affect experimental running gait data, respectively. An alternative approach that uses ellipse area as a bivariate measure of variability was proposed, applied to the same dataset, and compared to two popular methods of coordination variability analysis. RESULTS: The simulated data showed the existence of a statistical artefact, which was greater for shorter VC vector lengths in coordination variability measures that used circular statistics. The statistical artefact typically manifests itself as inflated peaks in the coordination variability trace. The experimental data also indicated that short vector lengths are prevalent in running gait. The Ellipse Area Method of coordination variability was not affected by the VC vector length. SIGNIFICANCE: Researchers using current VC variability measures should be particularly aware of the possible effect of the statistical artefact on their data, which is most likely to occur when vector lengths are short. The novel approach we have suggested for calculating VC coordination variability may provide the foundation for future research into vector coding coordination variability.

Considerations that affect optimised simulation in a running jump for height.

This study used a computer simulation model to investigate various considerations that affect optimum peak height in a running jump. A planar eight-segment computer simulation model with extensor and flexor torque generators at five joints was formulated and customised to an elite male high jumper. A simulation was matched to a recorded high jumping performance by varying the activation profiles of each of the torque generators giving a simulated peak height of 1.99m compared to the recorded performance of 2.01 m. In order to maximise the peak height reached by the mass centre in the flight phase, the activation profiles were varied, keeping the same initial conditions as in the matching simulation. Optimisations were carried out without any constraints, with constraints on the angular momentum at take-off, with further constraints on joint angles, and with additional requirements of robustness to perturbations of activation timings. A peak height of 2.37 m was achieved in the optimisation without constraints. Introducing the three constraints in turn resulted in peak heights of 2.21, 2.14 and 1.99m. With all three types of constraints included, the peak height was similar to that achieved in the recorded performance. It is concluded that such considerations have a substantial influence on optimum technique and must be included in studies using optimised simulations.

Contributions of the non-kicking-side arm to rugby place-kicking technique.

To investigate non-kicking-side arm motion during rugby place kicking, five experienced male kickers performed trials under two conditions, both with an accuracy requirement but one with an additional maximal distance demand. Joint centre coordinates were obtained at 120 Hz during kicking trials and a three-dimensional model was created to enable the determination of segmental contributions to whole-body angular momentum. All kickers possessed minimal non-kicking-side arm angular momentum about the global medio-lateral axis. The more accurate kickers exhibited greater non-kicking-side arm angular momentum about the global antero-posterior axis. This augmented the whole-body antero-posterior angular momentum, and altered the whole-body lateral lean at ball contact. The accurate kickers also exhibited greater non-kicking-side arm angular momentum about the global longitudinal axis, which opposed the kicking leg longitudinal angular momentum and attenuated the whole-body longitudinal angular momentum. All participants increased the longitudinal angular momentum of the non-kicking-side arm in the additional distance demand condition, except for one participant whose accuracy decreased, suggesting that the longitudinal angular momentum of the non-kicking-side arm assists maintenance of accuracy in maximum distance kicking. Goal kickers should be encouraged to produce non-kicking-side arm rotations about both the antero-posterior and longitudinal axes, as these appear important for both the initial achievement of accuracy, and for maintaining accuracy during distance kicking.

Determination of subject-specific model parameters for visco-elastic elements.

The determination of subject-specific model parameter values is necessary in order for a computer simulation model of human motion to be evaluated quantitatively. This study used an optimisation procedure along with a kinematically driven simulation model of the contact phase in running jumps to determine the elastic parameters of segmental wobbling masses and the foot-ground interface. Kinetic and kinematic data were obtained on running jumps for height and distance performed by an elite male high jumper. Stiffness and damping coefficients of the visco-elastic elements in the model were varied until the difference between simulation and performance was minimised. Percentage differences of 6% and 9% between the simulated and recorded performances were obtained in the jumps for height and distance, respectively. When the parameters obtained from the jump for height were used in a simulation of the jump for distance (and vice versa), there was poor agreement with the recorded jump. On the other hand, a common set of visco-elastic parameters were obtained using the data from both recorded jumps resulting in a mean difference of only 8% (made up of 7% and 10%) between simulation and performance that was almost as good as the individual matches. Simulations were not overly sensitive to perturbations of the common set of visco-elastic parameters. It is concluded that subject-specific elastic parameters should be calculated from more than a single jump in order to provide a robust set of values that can be used in different simulations.

Modelling the maximum voluntary joint torque/angular velocity relationship in human movement.

The force exerted by a muscle is a function of the activation level and the maximum (tetanic) muscle force. In "maximum" voluntary knee extensions muscle activation is lower for eccentric muscle velocities than for concentric velocities. The aim of this study was to model this "differential activation" in order to calculate the maximum voluntary knee extensor torque as a function of knee angular velocity. Torque data were collected on two subjects during maximal eccentric-concentric knee extensions using an isovelocity dynamometer with crank angular velocities ranging from 50 to 450 degrees s(-1). The theoretical tetanic torque/angular velocity relationship was modelled using a four parameter function comprising two rectangular hyperbolas while the activation/angular velocity relationship was modelled using a three parameter function that rose from submaximal activation for eccentric velocities to full activation for high concentric velocities. The product of these two functions gave a seven parameter function which was fitted to the joint torque/angular velocity data, giving unbiased root mean square differences of 1.9% and 3.3% of the maximum torques achieved. Differential activation accounts for the non-hyperbolic behaviour of the torque/angular velocity data for low concentric velocities. The maximum voluntary knee extensor torque that can be exerted may be modelled accurately as the product of functions defining the maximum torque and the maximum voluntary activation level. Failure to include differential activation considerations when modelling maximal movements will lead to errors in the estimation of joint torque in the eccentric phase and low velocity concentric phase.