ET, −18%, P ≤ 0.01), and voluntary activation measured with TMS (−11, −15 and −17%, respectively, P ≤ 0.01) were evident. The fatigue response was robust across both trials; the change in MVC at each time point demonstrated a good level of reliability (CV range 6-11%; ICC 2,1 0.83-0.94), whilst the responses identified with motor nerve stimulation showed a moderate level of reliability (CV range 5-18%; ICC 2,1 0.63-0.89) and the data obtained with motor cortex stimulation showed an excellent level of reliability (CV range 3-6%; ICC 2,1 0.90-0.98). Conclusion Simulated soccer exercise induces a significant level of fatigue, which is consistent on repeat tests, and involves both central and peripheral mechanisms. Keywords

Harper, LD, Hunter, R, Parker, P, Goodall, S, Thomas, K, Howatson, G, West, DJ, Stevenson, E, and Russell, M. Test-retest reliability of physiological and performance responses to 120 minutes of simulated soccer match play. J Strength Cond Res 30(11): 3178-3186, 2016-This study investigated the test-retest reliability of physiological and performance responses to 120 minutes (90 minutes plus 30 minutes extra-time [ET]) of the soccer match simulation (SMS). Ten university-standard soccer players completed the SMS on 2 occasions under standardized conditions. Capillary and venous blood was taken pre-exercise, at half-time, and at 90 and 120 minutes, with further capillary samples taken every 15 minutes throughout the exercise. Core temperature (Tcore), physical (20- and 15-m sprint speeds and countermovement jump height), and technical (soccer dribbling) performance was also assessed during each trial. All variables except blood lactate demonstrated no systematic bias between trials (p > 0.05). During the last 15 minutes of ET, test-rest reliability (coefficient of variation %, Pearson's r, respectively) was moderate to strong for 20-m sprint speed (3.5%, 0.71), countermovement jump height (4.9%, 0.90), dribble speed (2.8%, 0.90), and blood glucose (7.1%, 0.93), and very strong for Tcore (1.2%, 0.99). Moderate reliability was demonstrated for 15-m sprint speed (4.6%, 0.36), dribble precision (11.5%, 0.30), plasma insulin (10.3%, 0.96), creatine kinase ([CK] 28.1%, 0.38), interleukin-6 (24%, 0.99), nonesterified fatty acids ([NEFA] 13.2%, 0.73), glycerol (12.5%, 0.86), and blood lactate (18.6%, 0.79). In the last 15 minutes of ET, concentrations of blood glucose and lactate and sprint and jump performances were reduced, whereas Tcore, NEFA, glycerol, and CK concentrations were elevated (p ≤ 0.05). The SMS is a reliable protocol for measuring responses across the full 120 minutes of soccer-specific exercise. Deleterious effects on performance and physiological responses occur during ET.

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For over 3 million years hominins held stone-cutting tools in the hand, gripping the portion of tool displaying a sharp cutting edge directly. During the late Middle Pleistocene human populations started to produce hafted composite knives, where the stone element displaying a sharp cutting edge was secured in a handle. Prevailing archaeological literature suggests that handles convey benefits to tool users by increasing cutting performance and reducing musculoskeletal stresses, yet to date these hypotheses remain largely untested. Here, we compare the cutting performance of hafted knives, ‘basic’ flake tools, and large bifacial tools during two standardized cutting tasks. Going further, we examine the comparative ergonomics of each tool type through electromyographic (EMG) analysis of nine upper limb muscles. Results suggest that knives (1) recruit muscles responsible for digit flexion (i.e. gripping) and in-hand manipulation relatively less than alternative stone tool types and (2) may convey functional performance benefits relative to unhafted stone tool alternatives when considered as a generalised cutting tool. Furthermore, our data indicate that knives facilitate greater muscle activity in the upper arm and forearm, potentially resulting in the application of greater cutting forces during tool use. Compared to unhafted prehistoric alternatives, hafted stone knives demonstrate increased ergonomic properties and some functional performance benefits. These factors would likely have contributed to the invention and widespread adoption of hafted stone knives during the late Middle Pleistocene.