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The article addresses some of the novel technologies being increasingly utilised within sports biomechanics and highlights key factors to be considered in best practice. Topics include the benefits of these technologies, categories of measurements that can be obtained with inertial measurement units (IMUs,) and considerations for fixation selecting and using IMUs.

The purpose of this study was to examine the role of neuromotor noise on golf swing performance in high- and low-handicap players. Selected two-dimensional kinematic measures of 20 male golfers (n = 10 per high- or low-handicap group) performing 10 golf swings with a 5-iron club was obtained through video analysis. Neuromotor noise was calculated by deducting the standard error of the measurement from the coefficient of variation obtained from intra-individual analysis. Statistical methods included linear regression analysis and one-way analysis of variance using SPSS. Absolute invariance in the key technical positions (e.g., at the top of the backswing) of the golf swing appears to be a more favorable technique for skilled performance. (Contains 6 tables and 3 figures.)

The article highlights that when conducting biomechanics and footwear studies using three-dimensional motion capture, it is important to adhere to standardized reporting guidelines to ensure that your results are reproducible and can be accurately compared to other studies. Topics include some suggested reporting guidelines such as participant demographics, equipment and data collection, and experimental procedures.

The upper limbs are important in gymnastics vaulting, as the success of the flight phase is dependent on a quick and forceful push-off from the vault. This places the upper limbs under stress, which has been associated with pain and injury. This study aimed to quantify forearm segmental loading and symmetry when performing foundation to advanced-level vaulting skills during training. Twelve advanced-level artistic gymnasts (female, n = 6; male, n = 6) wore bilaterally forearm-mounted inertial measurement units while completing their vaulting sessions. The peak resultant acceleration for the leading and non-leading forearms during contact were calculated. Female gymnasts performed variations of Yurchenko vaults, while male gymnasts performed Handspring and Tsukahara vaults. Descriptive statistics (median and inter-quartile range), symmetry index scores, and total session impact load (measure of cumulative loading) were calculated between the lead and non-lead forearms. High asymmetrical loading was identified for some Yurchenko, Handspring, and Tsukahara vaults, with large variations identified between gymnasts. Some gymnasts experienced greater loading at their lead forearm, while others experienced greater loading at their non-lead forearm. Results indicate that limb loading patterns in advanced gymnastics are highly individualised, indicating that individual analysis is needed to identify gymnasts (or limbs) at an increased risk for overuse injury. [ABSTRACT FROM AUTHOR]

This study examined the agreement between force platform and inertial measurement unit (IMU) measures of backward somersault landings. Seven female gymnasts performed three trials, taking off from a 90 cm vaulting box and using competition landing technique. Two force platforms (1000 Hz) covered with a 6.4 cm thick carpeted landing surface measured the ground reaction forces. One inertial measurement unit (500 Hz) fixed on the second thoracic vertebra measured peak resultant deceleration of the gymnast. Measurement agreement between vertical and resultant peak force measures, and resultant peak force and peak deceleration was assessed using mean differences, Pearson's correlation, and Cohen's effect size (ES) statistics. There was perfect measurement agreement between vertical and resultant peak forces (R = 1.0, p < 0.001; ES = 0.005), but only moderate measurement agreement between resultant peak force and peak resultant deceleration (Mean Difference = −2.16%, R = 0.4, p = ns; ES = 0.121). Backward somersault landings can be assessed using either uni-axial or tri-axial force platforms to measure ground impact load/force, as the landing movements are almost purely vertical. However, force measures are not the same as peak resultant decelerations from IMUs which give an indication of impact shock. Landing load/shock measures are potentially important for injury prevention. [ABSTRACT FROM AUTHOR]

The present study assessed the anthropometric profile (International Society for the Advancement of Kinanthropometry protocol), flexibility, muscular strength, and endurance of 20 male golfers. These data were collected in order to determine: a) the relationship between these kinanthropometric measures and clubhead velocity; and b) if these measures could distinguish low-handicap (LHG) and high-handicap (HHG) golfers. Ten LHG (handicap of 0.3 [+ or -] 0.5) and 10 HHG (handicap of 20.3 [+ or -] 2.4) performed 10 swings for maximum velocity and accuracy with their own 5-iron golf club at a wall-mounted target. LHG hit the target significantly more (115%) and had a 12% faster clubhead velocity than HHG (p < 0.01 ). The LHG also had significantly (28%) greater golf swing--specific cable woodchop (GSCWC) strength (p < 0.01) and tendencies for greater (30%) bench press strength and longer (5%) upper am and total arm (4%) length and less (24%) right hip internal rotation than HHG (0.01 < p < 0.05). GSCWC strength was significantly correlated to clubhead velocity (p < 0.01), with bench press and hack squat strength as well as upper arm and total arm length also approaching significance (0.01 < p < 0.05). Golfers with high GSCWC strength and perhaps greater bench press strength and longer arms may therefore be at a competitive advantage, as these characteristics allow the production of greater clubhead velocity and resulting ball displacement. Such results have implications for golf talent identification programs and for the prescription and monitoring of golf conditioning programs. While golf conditioning programs may have many aims, specific trunk rotation exercises need to be included if increased clubhead velocity is the goal. Muscular hypertrophy development may not need to be emphasized as it could reduce golf performance by limiting range of motion and/ or increasing moment of inertia. KEY WORDS anthropometry, golf, range of motion, resistance training, specificity, talent identification

The purpose of this study was to examine the changes to block start and early acceleration sprint kinematics with resisted sled towing. Ten male sprinters performed 12 sprints (four each of unresisted and approximately 10 and 20% body mass IBM]) for 10 m from a block start. Two-dimensional high-speed video footage (250 Hz) of the starting action and the first three steps of each sprint were recorded to enable the sagittal sprinting kinematic parameters to be obtained using APAS motion analysis software. The overall results of this study indicated that early acceleration sprint performance from starting blocks decreases with increasing load during resisted sled towing. A load of approximately 10% BM had no 'negative' effect on sprint start technique or step kinematic variables measured in this study (with the exception of one variable) and was also within the 'no greater than 10% decrease in speed' limits suggested by Jakalski. Towing a load of approximately 20% BM increased the time spent in the starting blocks and induced a more horizontal position during the push-off (drive) phase. The approximately 20% BM load also caused the sprinters to shorten their initial strides (length), which may have resulted from the decreased flight distances. Such results suggest that the kinematic changes produced by the 10% BM load may be more beneficial than those of the 20% BM load. Future training studies will, however, need to investigate how these acute changes in sprinting technique impact on long-term adaptations in sprinting performance from resisted sprinting. KEY WORDS kinematics, resisted sprints, sprint running, sprint start

The magnitude of loading artistic gymnasts experience during training is currently unknown. Inertial measurement units (IMUs) could assess loading, although the reliability of these devices must be established prior to implementation into the training environment. This study aimed to determine inter-trial reliability of using IMeasureU Blue Thunder IMUs to assess upper and lower limb loading when performing foundation gymnastics skills. A secondary aim investigated the effect of raw and filtered acceleration signals on reliability results. Sixteen competitive level artistic gymnasts (male, n = 8; female, n = 8) performed seven gymnastics skills while wearing four IMUs (upper back, lower back, forearm and tibia). The peak resultant acceleration (PRA) during ground contact for all skills was exported from raw and filtered acceleration data (fourth-order zero-lag Butterworth filter with 85 Hz cut-off). Descriptive statistics (median and inter-quartile range), Friedman's ANOVA, intra-class correlations, coefficient of variation, mean difference and Cohen's effect sizes were calculated. Overall, the IMU PRA measures showed very good inter-trial reliability, however filtered signals improved reliability statistics for five variables compared to raw. The forearm- and tibia-mounted IMUs demonstrated improved reliability (very good reliability) compared to back positions (good reliability). IMUs are considered reliable devices to measure upper and lower limb loading in gymnastics. [ABSTRACT FROM AUTHOR]

A number of methods are used to measure lower extremity musculoskeletal stiffness, but there is a paucity of research examining the reliability of these techniques. Therefore, we investigated the reliability of vertical, leg, knee, and ankle stiffness during overground running and hopping in 20 active men. Participants were required to run on a 10 m overground runway at 3.83 m/s (actual; 3.35 ± 0.12 m/s) and to hop in place at 2.2 Hz (actual; 2.37 ± 0.03 Hz), and at a self-selected frequency (actual; 2.05 ± 0.12 Hz) and at 2.2 Hz (actual; 2.39 ± 0.04 Hz). Reliability was determined using the intraclass correlation coefficient, coefficient of variation, mean differences, and Cohen's effect sizes. There was good reliability for vertical stiffness, moderate reliability for leg stiffness, and poor reliability for knee and ankle stiffness during the running task. Similar results were observed during the 2.2 Hz hopping tasks, with good reliability displayed for vertical stiffness and poor reliability for ankle and knee stiffness. In conclusion, our results suggest that vertical stiffness is a reliable measure when running at 3.83 m/s and hopping at 2.2 Hz. [ABSTRACT FROM AUTHOR]

This study assessed measurement agreement of jump-height measures derived from a portable forceplate sampling at 500 Hz. Female (n = 42) and male (n = 30) participants (total N = 72, age = 19.7 ± 2.8 y, height = 174.5 ± 9.3 cm, mass = 71.4 ± 12.8 kg) performed 25 separate maximal jump attempts. This incorporated 5 sets of 5 single jumps. One minute of rest was allowed between jump attempts, with a 3-min rest period between sets. For each participant, the best jump height for each set of 5 jumps was kept for analysis. No systematic bias was identified, and the best jump height was stable within participants across all 5 sets of jumps. Therefore, factors such as fatigue and learning did not affect the measures. Females did jump lower (P = < .0001) than their male counterparts, justifying additional analysis of agreement for the 2 gender groups. Heteroscedasticity was found, so ratio limits of agreement (LOAs) were calculated by using the antilog of the log-transformed data. The calculated ratio LOAs were ×/÷ 1.08 for the total group, ×/÷ 1.08 for females, and ×/÷ 1.08 for males. From the calculated ratio LOA, the jump protocol was shown to provide stable measures of jump height. In addition, the ratio LOA can be helpful to interpret findings from research that report jump height derived from the same protocol and assessing participants from the studied population (ie, active university-age male, female, or combined-gender groups). [ABSTRACT FROM AUTHOR]

Adjustments to gait were examined when positioning the foot within a narrow target at the end of an approach for two impact conditions, hard and soft. Participants (6 M, 6 F) ran toward a target of three lengths along a 10-m walkway consisting of two marker strips with alternating black and white 0.5-m markings. Five trials were conducted for each target length and impact task, with trials block randomized between the 6 participants of each gender. A 50-Hz digital video camera panned and filmed each trial from an elevated position adjacent to the walkway. Video footage was digitized to deduce the gait characteristics. A linear speed/accuracy tradeoff between target length and approach time was found for both impact tasks (hard, r = 0.99, p < 0.01; soft, r = 0.96, p < 0.05). For the hard-impact task, visual control time increased linearly (r = 0.99, p < 0.05) when whole-body approach velocity decreased. Visual control time was unaffected by whole-body approach velocity in the soft-impact task. A constant tau-margin of 1.08 describes the onset of visual control when approaching a target while running, with the control of braking during visual control described by a tau-dot of -0.85. Further research is needed to examine the control of braking in different targeting tasks. [ABSTRACT FROM AUTHOR]

Presents a study on speed-accuracy trade-off in human gait control when running. Significance of accurate foot placement in gait; Discussions on stride regulations in controlling foot position; Relation between speed and accuracy in gait.

Double-leg repeated jumping tasks are commonly used as measures of lower limb stiffness in exercise science research. Within similar stiffness calculations, variation in data-reduction criteria exists. The impact of these varied data-reduction methods on stiffness measures is unknown. Sixteen adolescent female participants from varied physical activity backgrounds performed 15 self-paced, bent-knee continuous jumps (CJb) on two force plates. Leg stiffness was calculated as the ratio of the peak force and the centre of mass displacement for each contact. Using combinations of criteria based on previous literature, 83 data-reduction methods were applied to the raw data. Data reduction suitability was assessed based on intra-trial reliability, the number of participants excluded and the average contacts excluded. Four data-reduction methods were deemed suitable for use with adolescent female populations, with three consecutive contacts within 1 SD of the average jump frequency considered optimal. The average individual stiffness values were not greatly influenced by the data-reduction method; however, for a single participant, a stiffness change of up to 6 kN · m−1(30%) was observed. The role and potential impact of data-reduction methods used to evaluate measures of lower limb stiffness during repeated jumping tasks warrants consideration. [ABSTRACT FROM AUTHOR]