JL , Hughes MG , McMaster D . The reliability of jump kinematics and kinetics in children of different maturity status . J Strength Cond Res . 2012 ; 26 ( 4 ): 1015 – 1026 . PubMed doi:10.1519/JSC.0b013e31822dcec7 10.1519/JSC.0b013e31822dcec7 22446671 18. Jaric S , Mirkov D , Markovic
Search Results
The Neuromuscular Determinants of Unilateral Jump Performance in Soccer Players Are Direction-Specific
Conall F. Murtagh, Christopher Nulty, Jos Vanrenterghem, Andrew O’Boyle, Ryland Morgans, Barry Drust, and Robert M. Erskine
The Effects of Nutritional Supplementation Throughout an Endurance Run on Leucine Kinetics during Recovery
Sharon L. Miller, P. Courtney Gaine, Carl M. Maresh, Lawrence E. Armstrong, Cara B. Ebbeling, Linda S. Lamont, and Nancy R. Rodriguez
This study determined the effect of nutritional supplementation throughout endurance exercise on whole-body leucine kinetics (leucine rate of appearance [Ra], oxidation [Ox], and nonoxidative leucine disposal [NOLD]) during recovery. Five trained men underwent a 2-h run at 65% VO2max, during which a carbohydrate (CHO), mixed protein-carbohydrate (milk), or placebo (PLA) drink was consumed. Leucine kinetics were assessed during recovery using a primed, continuous infusion of 1-13C leucine. Leucine Ra and NOLD were lower for milk than for PLA. Ox was higher after milk-supplemented exercise than after CHO or PLA. Although consuming milk during the run affected whole-body leucine kinetics, the benefits of such a practice for athletes remain unclear. Additional studies are needed to determine whether protein supplementation during exercise can optimize protein utilization during recovery.
Why Do Children Have Faster VO2 Kinetics?
Raffy Dotan
The May 2019 issue of Pediatric Exercise Science features a review of oxygen uptake kinetics in youth by Dr. McNarry ( 7 ). The author ought to be commended for a comprehensive and generally well-referenced coverage of the topic. However, dealing with children, and being published in Pediatric
Differences in Oxygenation Kinetics Between the Dominant and Nondominant Flexor Digitorum Profundus in Rock Climbers
David Giles, Vanesa España Romero, Inmaculada Garrido, Alejandro de la O Puerta, Keeron Stone, and Simon Fryer
Purpose:
To examine differences in oxygenation kinetics in the nondominant and dominant flexor digitorum profundus (FDP) of rock climbers.
Methods:
Participants were 28 sport climbers with a range of on-site abilities (6a+ to 8a French Sport). Using near-infrared spectroscopy, oxygenation kinetics of the FDP was assessed by calculating the time to half recovery (t 1/2 recovery) of the tissue-saturation index (TSI) after 3–5 min of ischemia.
Results:
A 2-way mixed-model ANOVA found a nonsignificant interaction (P = .112) for TSI by sex. However, there was a significant main effect (P = .027) of handedness (dominant vs nondominant FDP). The dominant forearm recovered 13.6% faster (t 1/2 recovery mean difference = 1.12 s, 95% CI 0.13–2.10 s) than the nondominant FDP. This was not affected by 6-mo on-site climbing ability or sex (P = .839, P = .683).
Conclusions:
Significant intraindividual differences in oxygenation kinetics of the FDP were found. Improvements in oxygenation kinetics in the FDP are likely due to the abilities of the muscle to deliver, perfuse, and consume oxygen. These enhancements may be due to structural adaptations in the microvasculature, such as an increase in capillary density and enhanced improvement in capillary filtration.
Medial Compressible Forefoot Sole Elements Reduce Ankle Inversion in Lateral SSC Jumps
Jana Fleischmann, Guillaume Mornieux, Dominic Gehring, and Albert Gollhofer
Sideward movements are associated with high incidences of lateral ankle sprains. Special shoe constructions might be able to reduce these injuries during lateral movements. The purpose of this study was to investigate whether medial compressible forefoot sole elements can reduce ankle inversion in a reactive lateral movement, and to evaluate those elements’ influence on neuromuscular and mechanical adjustments in lower extremities. Foot placement and frontal plane ankle joint kinematics and kinetics were analyzed by 3-dimensional motion analysis. Electromyographic data of triceps surae, peroneus longus, and tibialis anterior were collected. This modified shoe reduced ankle inversion in comparison with a shoe with a standard sole construction. No differences in ankle inversion moments were found. With the modified shoe, foot placement occurred more internally rotated, and muscle activity of the lateral shank muscles was reduced. Hence, lateral ankle joint stability during reactive sideward movements can be improved by these compressible elements, and therefore lower lateral shank muscle activity is required. As those elements limit inversion, the strategy to control inversion angles via a high external foot rotation does not need to be used.
Lower Extremity Joint Work During Acceleration, Deceleration, and Steady State Running
D.S. Blaise Williams III, Jonathan H. Cole, and Douglas W. Powell
Running during sports and for physical activity often requires changes in velocity through acceleration and deceleration. While it is clear that lower extremity biomechanics vary during these accelerations and decelerations, the work requirements of the individual joints are not well understood. The purpose of this investigation was to measure the sagittal plane mechanical work of the individual lower extremity joints during acceleration, deceleration, and steady-state running. Ten runners were compared during acceleration, deceleration, and steady-state running using three-dimensional kinematics and kinetics measures. Total positive and negative joint work, and relative joint contributions to total work were compared between conditions. Total positive work progressively increased from deceleration to acceleration. This was due to greater ankle joint work during acceleration. While there was no significant change in total negative work during deceleration, there was a greater relative contribution of the knee to total negative work with a subsequent lower relative ankle negative work. Each lower extremity joint exhibits distinct functional roles in acceleration compared with deceleration during level running. Deceleration is dominated by greater contributions of the knee to negative work while acceleration is associated with a greater ankle contribution to positive work.
Age-Related Changes in Performance and Recovery Kinetics in Masters Athletes: A Narrative Review
Nattai Borges, Peter Reaburn, Matthew Driller, and Christos Argus
Despite increasing participation rates in masters sport and extensive research examining age-related changes in performance, little is known about the effect of age on recovery kinetics in masters athletes. This narrative review focuses on the relationship between aging and sport participation, and the effect on both performance and recovery following an exercise bout. Current research suggests the effect of age on performance and recovery may be smaller than originally suggested and that increasing sedentary lifestyles appear to play a larger role in any observed decrements in performance and recovery in masters athletes. Currently, it appears that performance decrements are inevitable with age. However, performance capacities can be maintained through systematic physical training. Moreover, the limited current research suggests there may be an age effect on recovery kinetics following an exercise bout, although further research is required to understand the acute and chronic recovery processes in the masters athlete.
Consistent Immediate Effects of Foot Orthoses on Comfort and Lower Extremity Kinematics, Kinetics, and Muscle Activity
Anne Mündermann, Benno M. Nigg, R. Neil Humble, and Darren J. Stefanyshyn
In order to accommodate patients to new foot orthoses over time, two steps are required: The first is to obtain a baseline reading of the immediate effects across several weeks to ensure consistency. The second step is to look at changes with progressively longer wear periods similar to what occurs in general practice. This study addressed the first step. The purpose of this study was to determine whether the baseline reading of the immediate effects of foot orthoses on comfort and lower extremity kinematics, kinetics, and muscle activity is consistent between days. Participants were 21 recreational runners who volunteered for the study. Three orthotic conditions (posting, custom-molding, posting and custom-molding) were compared to a control (flat) insert. Lower extremity kinematic, kinetic, and EMG data were collected for 108 trials per participant and condition in 9 sessions for each person for running at 4 m/s. Comfort for all orthotic conditions was assessed in each session using a visual analog scale. Statistically significant session effects were detected using repeated-measures ANOVA (α = .05). Three of the 93 variables had a significant session effect. A significant interaction between orthotic condition and session was observed for 6 of the 93 variables. The results of this study showed that the effects of foot orthoses on comfort, lower extremity kinematics, kinetics, and muscle activity are consistent across a 3-week period when the wear time for each condition is restricted. Thus, foot orthoses lead to immediate changes in comfort, kinematics, kinetics, and muscle activity with limited use. These immediate effects of foot orthoses on comfort, kinematics, kinetics, and muscle activity are consistent between days.
Lower Extremity Kinematics and Kinetics When Landing From Unloaded and Loaded Jumps
Ina Janssen, Jeremy M. Sheppard, Andrew A. Dingley, Dale W. Chapman, and Wayne Spratford
Countermovement jumps loaded with a weighted vest are often used for the training of lower body power to improve jump performance. However, it is currently unknown how this added load affects the lower extremity kinematics and kinetics, in particular whether this results in an increased injury risk. Therefore, the purpose of this investigation was to determine how lower extremity kinematics and kinetics during landing are affected by loaded jumps as demonstrated in a volleyball block jump landing. Ten elite male volleyball players performed block jump landings in an unloaded and loaded (9.89 kg) condition. Kinematic and kinetic landing data from the three highest jumps were collected and assessed. Paired samples t test was used to establish whether load condition had a significant effect on lower extremity kinematics and kinetics. Hip flexion was significantly greater in the unloaded condition compared with the loaded condition (p = .004). There was no significant difference in any other kinematic or kinetic variables measures between the unloaded and loaded conditions. These results suggest that landing from loaded volleyball block jumps does not increase injury risk compared with unloaded jumps in elite male volleyball players.
Influence of Position and Power Output on Upper Limb Kinetics in Cycling
Antony Costes, Nicolas A. Turpin, David Villeger, Pierre Moretto, and Bruno Watier
Several suggestions on the upper limb involvement in cycling exist but, to date, no study has quantified upper limb kinetics in this task. The aim of this study was to determine how crank power and pedaling position (seated or standing) affect upper limb kinetics. Handlebar loadings and upper limb kinematics were collected from 17 participants performing seated or standing pedaling trials in a random order at 6 crank powers ranging from 20% (112 ± 19 W) to 120% (675 ± 113 W) of their spontaneous sit-to-stand transition power. An inverse dynamics approach was used to compute 3D moments, powers, and works at the wrist, elbow, and shoulder joints. Over 29 parameters investigated, increases in crank power were associated with increases in the magnitudes of 23 and 20 of the kinetic variables assessed in seated and standing positions, respectively. The standing position was associated with higher magnitudes of upper limb kinetics. These results suggest that both upper and lower limbs should be considered in future models to better understand whole body coordination in cycling.
