A Comprehensive Examination of Age-Related Lower Limb Muscle Function Asymmetries across a Variety of Muscle Action Types.

Previous research has found that lower limb muscle asymmetries increase with age and are linked to fall and injury risks. However, past studies lack a wide variety of muscle function modes and measures as well as comparison to a comparable younger age group. The purpose of this study was to examine age-related lower limb muscle function asymmetries across a variety of muscle action types and velocities in young and old adults.

Effects of Stroboscopic Vision on Depth Jump Motor Control: A Biomechanical Analysis.

Researchers commonly use the 'free-fall' paradigm to investigate motor control during landing impacts, particularly in drop landings and depth jumps (DJ). While recent studies have focused on the impact of vision on landing motor control, previous research fully removed continuous visual input, limiting ecological validity. The aim of this investigation was to evaluate the effects of stroboscopic vision on depth jump (DJ) motor control.

Effects of Multi-joint Eccentric Training on Muscle Function When Combined With Aquatic Plyometric Training: A Minimal Dose, Mixed Training Study.

Objectives: To examine the effects of a combined eccentric overload and aquatic-based plyometric training program on muscle function/performance measures and soreness versus an eccentric-only training protocol using a minimal dose training paradigm.

Methods: Twenty-five participants were randomized into either an eccentric-only training group (ECC) or a combined eccentric and aquatic plyometric group (ECC + AQP). The ECC group performed eccentric training once per week for 6-weeks while the ECC + AQP group performed the same eccentric training but with an additional aquatic plyometric training session.

Kinetics of Depth Jumps Performed by Female and Male National Collegiate Athletics Association Basketball Athletes and Young Adults.

The depth jump (DJ) is commonly used to evaluate athletic ability, and has further application in rehabilitation and injury prevention. There is limited research exploring sex-based differences in DJ ground reaction force (GRF) measures. This study aimed to evaluate for sex-based differences in DJ GRF measures and determine sample size thresholds for binary classification of sex.

Transfer Effects of a Multiple-Joint Isokinetic Eccentric Resistance Training Intervention to Nontraining-Specific Traditional Muscle Strength Measures.

Relatively few investigations have examined the transfer effects of multiple-joint isokinetic eccentric only (MJIE) resistance training on non-specific measures of muscle strength. This study investigated the transfer effects of a short-term MJIE leg press (Eccentron) resistance training program on several non-specific measures of lower-body strength. Fifteen participants performed Eccentron training three times/week for four weeks and were evaluated on training-specific Eccentron peak force (EccPF), nontraining-specific leg press DCER one-repetition maximum (LP 1 RM), and peak torques of the knee extensors during isokinetic eccentric (Ecc30), isokinetic concentric (Con150) and isometric (IsomPT) tasks before and after the training period.

Test-retest reliability of the 5-minute psychomotor vigilance task in working-aged females.

Background: The psychomotor vigilance task (PVT) is a commonly used test that effectively assesses neurobehavioral alertness. The originally developed PVT is 10 minutes in duration, which presents practical and logistical issues, particularly when administered to large samples or on a repetitive basis. More recently the PVT has been used in both 3- and 5-minute formats.

Association and Agreement between Reactive Strength Index and Reactive Strength Index-Modified Scores.

Since the reactive strength index (RSI) and reactive strength index-modified (RSI-mod) share similar nomenclature, they are commonly referred as interchangeable measures of agility in the sports research literature. The RSI and RSI-mod are most commonly derived from the performance of depth jumping (DJ) and countermovement jumping (CMJ), respectively. Given that DJ and CMJ are plyometric movements that differ materially from biomechanical and neuromotor perspectives, it is likely that the RSI and RSI-mod measure distinct aspects of neuromuscular function.

Predictive Ability of Body Fat Percentage and Thigh Anthropometrics on Tissue Cooling During Cold-Water Immersion.

Context: Cold-water immersion (CWI) is a common aid in exercise recovery. The effectiveness of CWI depends on the magnitude of muscle and core cooling. Individual cooling responses to CWI vary and are likely influenced by the CWI dose and individual physiological characteristics.

Effect of stroboscopic vision on depth jump performance in female NCAA Division I volleyball athletes.

Anticipation of ground reaction force (GRF) in depth jumping requires multisensory integration of exteroceptive, vestibular, and proprioceptive inputs. Vision contributes to the anticipation of GRF in drop landings and may influence depth jump performance when disrupted. The purpose of this investigation was to evaluate the effects of stroboscopic vision on depth jump performance.

A Mixed-Methods Approach to Evaluating the Internal Validity of the Reactive Strength Index.

The reactive capacity of the muscle-tendon complex is commonly assessed using the reactive strength index (RSI). Conventionally, the RSI is a ratio of rebound jump height to ground contact time in depth jumping. Several assumptions regarding the linear mechanics acting through the whole-body center of gravity may threaten the internal validity of computation and interpretation of RSI scores.

Water Immersion Affects Episodic Memory and Postural Control in Healthy Older Adults.

Background And Purpose: Previous research has reported that younger adults make fewer cognitive errors on an auditory vigilance task while in chest-deep water compared with on land. The purpose of this study was to extend this previous work to include older adults and to examine the effect of environment (water vs land) on linear and nonlinear measures of postural control under single- and dual-task conditions.

Methods: Twenty-one older adult participants (age = 71.

Biomechanical Comparison of Loaded Countermovement Jumps Performed on Land and in Water.

Louder, T, Bressel, E, Nardoni, C, and Dolny, D. Biomechanical comparison of loaded countermovement jumps performed on land and in water. J Strength Cond Res 33(1): 25-35, 2019-Researchers have observed physical improvements after the completion of aquatic-based jump training.

Biomechanical Comparison of Countermovement Jumps Performed on Land and in Water: Age Effects.

Context: The aquatic environment provides a low-impact alternative to land-based exercise and rehabilitation in older adults.

Objective: Evaluate the biomechanics of older adults and young adults performing jumping movements on land and in water.

Design And Setting: Cross-sectional, mixed-factorial experiment; adjustable-depth pool at sports medicine research facility.

Acute and chronic effects of aquatic treadmill training on land treadmill running kinematics: A cross-over and single-subject design approach.

The aim of this study was to determine if selected kinematic measures (foot strike index [SI], knee contact angle and overstride angle) were different between aquatic treadmill (ATM) and land treadmill (LTM) running, and to determine if these measures were altered during LTM running as a result of 6 weeks of ATM training. Acute effects were tested using 15 competitive distance runners who completed 1 session of running on each treadmill type at 5 different running speeds. Subsequently, three recreational runners completed 6 weeks of ATM training following a single-subject baseline, intervention and withdrawal experiment.

Mechanical parameters and flight phase characteristics in aquatic plyometric jumping.

Plyometric jumping is a commonly prescribed method of training focused on the development of reactive strength and high-velocity concentric power. Literature suggests that aquatic plyometric training may be a low-impact, effective supplement to land-based training. The purpose of the present study was to quantify acute, biomechanical characteristics of the take-off and flight phase for plyometric movements performed in the water.

Age-Related Changes in Postural Sway Are Not Consistent Between Land and Aquatic Environments.

Background And Purpose: Quantifying how the environment (land vs water) influences age-related changes in postural sway is important for the development of new therapies that improve balance. The authors are not aware of any previous studies that have compared postural sway in an aquatic environment between age groups or when water depth and/or perturbations are incorporated into the comparison. The purpose of this study was to compare the effect of water depth and jet intensity on postural sway in older and younger adults.

The Kinetic Specificity of Plyometric Training: Verbal Cues Revisited.

Plyometric training is a popular method utilized by strength and conditioning professionals to improve aspects of functional strength. The purpose of this study was to explore the influence of extrinsic verbal cueing on the specificity of jumping movements. Thirteen participants (age: 23.

Effect of Water Immersion on Dual-task Performance: Implications for Aquatic Therapy.

Background And Purpose: Much is known about cardiovascular and biomechanical responses to exercise during water immersion, yet an understanding of the higher-order neural responses to water immersion is unclear. The purpose of this study was to compare cognitive and motor performance between land and water environments using a dual-task paradigm, which served as an indirect measure of cortical processing.

Design: A quasi-experimental crossover research design is used.