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Kristof Kipp, Michael T. Kiely, Matthew D. Giordanelli, Philip J. Malloy and Christopher F. Geiser

The Reactive Strength Index (RSI) is a measure often used to quantify dynamic lower-extremity performance during a drop jump (DJ). 1 – 3 The RSI represents a highly reliable (ie, intraclass correlation coefficient > .90) and simple index of performance that is also easy to measure and interpret. 4

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Robin Healy, Ian C. Kenny and Andrew J. Harrison

strength can be assessed in the drop jump using the reactive strength index (RSI) performed using the combination technique. 7 Several authors have proposed that the RSI is an effective means of assessing the performance of an SSC task and can also provide an indication of an athlete’s vertical leg

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Paul Comfort, Christopher Thomas, Thomas Dos’Santos, Paul A. Jones, Timothy J. Suchomel and John J. McMahon

produced during a squat jump (SJ) or a countermovement jump (CMJ) to PF during the IMTP has been discussed in the literature. 9 , 10 , 18 – 21 This ratio is commonly referred to as the Dynamic Strength Index (DSI) or the dynamic-strength deficit and has been reported to be highly reliable (intraclass

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Carolyn M. Donaldson, Tracy L. Perry and Meredith C. Rose

The aim of this review is to provide an up-to-date summary of the evidence surrounding glycemic index (GI) and endurance performance. Athletes are commonly instructed to consume low-GI (LGI) carbohydrate (CHO) before exercise, but this recommendation appears to be based on the results of only a few studies, whereas others have found that the GI of CHO ingested before exercise has no impact on performance. Only 1 study was designed to directly investigate the impact of the GI of CHO ingested during exercise on endurance performance. Although the results indicate that GI is not as important as consuming CHO itself, more research in this area is clearly needed. Initial research investigating the impact of GI on postexercise recovery indicated consuming high-GI (HGI) CHO increased muscle glycogen resynthesis. However, recent studies indicate an interaction between LGI CHO and fat oxidation, which may play a role in enhancing performance in subsequent exercise. Despite the fact that the relationship between GI and sporting performance has been a topic of research for more than 15 yr, there is no consensus on whether consuming CHO of differing GI improves endurance performance. Until further well-designed research is carried out, athletes are encouraged to follow standard recommendations for CHO consumption and let practical issues and individual experience dictate the use of HGI or LGI meals and supplements before, during, and after exercise.

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Silvia Cabral, Renan A. Resende, Adam C. Clansey, Kevin J. Deluzio, W. Scott Selbie and António P. Veloso

High levels of gait asymmetry are associated with many pathologies. Our long-term goal is to improve gait symmetry through real-time biofeedback of a symmetry index. Symmetry is often reported as a single metric or a collective signature of multiple discrete measures. While this is useful for assessment, incorporating multiple feedback metrics presents too much information for most subjects to use as visual feedback for gait retraining. The aim of this article was to develop a global gait asymmetry (GGA) score that could be used as a biofeedback metric for gait retraining and to test the effectiveness of the GGA for classifying artificially-induced asymmetry. Eighteen participants (11 males; age 26.9 y [SD = 7.7]; height 1.8 m [SD = 0.1]; body mass 72.7 kg [SD = 8.9]) walked on a treadmill in 3 symmetry conditions, induced by wearing custom-made sandals: a symmetric condition (identical sandals) and 2 asymmetric conditions (different sandals). The GGA score was calculated, based on several joint angles, and compared between conditions. Significant differences were found among all conditions (P < .001), meaning that the GGA score is sensitive to different levels of asymmetry, and may be useful for rehabilitation and assessment.

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Louise Capling, Janelle A. Gifford, Kathryn L. Beck, Victoria M. Flood, Gary J. Slater, Gareth S. Denyer and Helen T. O’Connor

( Hu, 2002 ). A diet quality index or diet quality score applies a scoring system that compares usual intake or dietary patterns against dietary guidelines or other predefined criteria, with a higher score being positively associated with a more favorable dietary intake ( Kant, 1996 ; Waijers et

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Nathaniel S. Nye, Drew S. Kafer, Cara Olsen, David H. Carnahan and Paul F. Crawford

, 18 This is significant given the increasing rates of obesity; as of 2012, 34.9% of Americans aged 20 years and older were considered obese 19 [defined as body mass index (BMI) ≥ 30 kg/m 2 ], placing them at additional risk for lower extremity injury. The use of BMI as a measure of body habitus has

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João Pedro Nunes, Alex S. Ribeiro, Analiza M. Silva, Brad J. Schoenfeld, Leandro dos Santos, Paolo M. Cunha, Matheus A. Nascimento, Crisieli M. Tomeleri, Hellen C.G. Nabuco, Melissa Antunes, Letícia T. Cyrino and Edilson S. Cyrino

usually expressed by muscle strength per unit of muscle mass (mass quality index [MQI]; Barbat-Artigas, Rolland, Zamboni, & Aubertin-Leheudre, 2012 ; Fragala et al., 2015 ; McGregor et al., 2014 ). This ratio better reflects muscular conditioning than muscle strength and mass separately, especially in

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Mark Holten Mora-Jensen, Pascal Madeleine and Ernst Albin Hansen

Index finger tapping is a relatively simple motor task that is related to various everyday activities such as computer work and playing musical instruments. Furthermore, the task is widely applied in studies of both healthy individuals ( Hammond & Gunasekera, 2008 ; Hansen & Ohnstad, 2008

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John J. McMahon, Paul A. Jones, Timothy J. Suchomel, Jason Lake and Paul Comfort

The Reactive Strength Index (RSI) accounts for the duration of force production to achieve a given jump height by dividing jump height by ground-contact time. 1 RSI is a more easily obtainable metric than force-platform-derived variables, and it provides greater insight into neuromuscular and