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Sports, Volume 8, Issue 7 (July 2020) – 13 articles

Cover Story (view full-size image): Competition cessation and training facility closures during the current global pandemic have caused unique and fundamental problems for strength athletes (e.g., powerlifters and weightlifters). However, despite ongoing restrictions, evidence suggests that muscle strength, power, and mass can remain above baseline even after several months without training. Such losses can also be minimized by training just once a week or less. In addition, strength athletes may undergo a faster rate of readaptation during retraining. Lastly, unavoidable time off training and competition can be strategically used to overcome persistent injury, improve movement quality, set relevant goals, and improve psychological aspects of performance. View this paper
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20 pages, 3889 KiB  
Article
Validity of the Stryd Power Meter in Measuring Running Parameters at Submaximal Speeds
by Frank Imbach, Robin Candau, Romain Chailan and Stephane Perrey
Sports 2020, 8(7), 103; https://doi.org/10.3390/sports8070103 - 20 Jul 2020
Cited by 35 | Viewed by 6788
Abstract
This study assessed the Stryd running power meter validity at sub-maximal speeds (8 to 19 km/h). Six recreational runners performed an incremental indoor running test. Power output (PO), ground contact time (GCT) and leg spring stiffness (LSS) were compared to reference measures recorded [...] Read more.
This study assessed the Stryd running power meter validity at sub-maximal speeds (8 to 19 km/h). Six recreational runners performed an incremental indoor running test. Power output (PO), ground contact time (GCT) and leg spring stiffness (LSS) were compared to reference measures recorded by portable metabolic analyser, force platforms and motion capture system. A Bayesian framework was conducted for systems validity and comparisons. We observed strong and positive linear relationships between Stryd PO and oxygen consumption ( R 2 = 0.82 , B F 10 > 100 ), and between Stryd PO and external mechanical power ( R 2 = 0.88 , B F 10 > 100 ). Stryd power meter underestimated PO ( B F 10 > 100 ) whereas GCT and LSS values did not show any significant differences with the reference measures ( B F 10 = 0.008 , B F 10 = 0.007 , respectively). We conclude that the Stryd power meter provides valid measures of GCT and LSS but underestimates the absolute values of PO. Full article
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16 pages, 652 KiB  
Article
Predictors of CrossFit Open Performance
by Gerald T. Mangine, Joy E. Tankersley, Jacob M. McDougle, Nathanael Velazquez, Michael D. Roberts, Tiffany A. Esmat, Trisha A. VanDusseldorp and Yuri Feito
Sports 2020, 8(7), 102; https://doi.org/10.3390/sports8070102 - 20 Jul 2020
Cited by 23 | Viewed by 4639
Abstract
The 2018 CrossFit Open (CFO) was the initial stage of an annual competition that consisted of five weekly workouts. Current evidence suggests that a variety of fitness parameters are important for progressing beyond this stage, but little is known about which are the [...] Read more.
The 2018 CrossFit Open (CFO) was the initial stage of an annual competition that consisted of five weekly workouts. Current evidence suggests that a variety of fitness parameters are important for progressing beyond this stage, but little is known about which are the most important. To examine relationships between CFO performance, experience, and physiological fitness, sixteen experienced (>2 years) athletes (30.7 ± 6.9 years, 171 ± 12 cm, 78.0 ± 16.2 kg) volunteered to provide information about their training and competitive history, and then complete a battery of physiological assessments prior to competing in the 2018 CFO. Athletes’ resting energy expenditure, hormone concentrations, body composition, muscle morphology, cardiorespiratory fitness, and isometric strength were assessed on two separate occasions. Spearman correlations demonstrated significant (p < 0.05) relationships between most variables and performance on each workout. Stepwise regression revealed competition experience (R2 = 0.31–0.63), body composition (R2 = 0.55–0.80), vastus lateralis cross-sectional area (R2 = 0.29–0.89), respiratory compensation threshold (R2 = 0.54–0.75), and rate of force development (R2 = 0.30–0.76) to be the most common predictors. Of these, body composition was the most important. These fitness parameters are known targets with established training recommendations. Though preliminary, athletes may use these data to effectively train for CFO competition. Full article
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13 pages, 1623 KiB  
Article
The Effects of Loaded Plyometric Exercise during Warm-Up on Subsequent Sprint Performance in Collegiate Track Athletes: A Randomized Trial
by Kalin A. Tomlinson, Ken Hansen, Daniel Helzer, Zakkoyya H. Lewis, Whitney D. Leyva, Meghan McCauley, William Pritchard, Emma Silvestri, Monica Quila, Michael Yi and Edward Jo
Sports 2020, 8(7), 101; https://doi.org/10.3390/sports8070101 - 17 Jul 2020
Cited by 4 | Viewed by 4561
Abstract
Prior evidence demonstrates the efficacy by which plyometric activities during warm-up conditions augment the subsequent performance in power-centric exercise. We investigated the acute effects of loaded jump squats incorporated into a standard sprinters’ warm-up protocol on subsequent sprint performance in collegiate track athletes. [...] Read more.
Prior evidence demonstrates the efficacy by which plyometric activities during warm-up conditions augment the subsequent performance in power-centric exercise. We investigated the acute effects of loaded jump squats incorporated into a standard sprinters’ warm-up protocol on subsequent sprint performance in collegiate track athletes. Sprint times of 22 male and female collegiate track athletes were measured in 10-m intervals during a 30-m sprint trial following a standard sprinters’ warm-up routine with or without plyometric exercise. Subjects were tested on two separate occasions, once with loaded jump squats as the experimental treatment (two sets of eight jumps, load = 13% bodyweight) (PLYO) and once with time-equated rest as the control treatment (CON). Treatments were implemented following a standard sprinters’ warm-up routine familiar to the subjects. A dependent T-test was used for comparison of sprint interval times between conditions with a significant effect indicated by a p-value < 0.05. Sprint time did not differ between CON vs. PLYO at the 10 m (PLYO = 1.90 ± 0.12 s vs. CON = 1.90 ± 0.11 s, p = 0.66), 20 m (PLYO = 3.16 ± 0.21 s vs. CON = 3.15 ± 0.19 s, p = 0.53), and 30 m (PLYO = 4.32 ± 0.32 s vs. CON = 4.31 ± 0.28 s, p = 0.61) intervals. There was no interaction between treatment and sex, sex-specific ranking (above vs. below sex-specific mean), or sprint event (short vs. short–long vs. long) for 10 m, 20 m, or 30-m interval sprint times. At least within the limits of the current investigation, no evidence was provided to suggest that jump squats loaded at 13% bodyweight are an effective means to acutely potentiate sprint performance in collegiate track athletes. However, a further examination of responders indicates that the present loaded jump squat protocol may preferentially potentiate sprint performance in faster male athletes. Full article
(This article belongs to the Special Issue Optimization of Human Performance and Health)
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16 pages, 1442 KiB  
Review
Global Challenges of Being a Strength Athlete during a Pandemic: Impacts and Sports-Specific Training Considerations and Recommendations
by Christopher Latella and G. Gregory Haff
Sports 2020, 8(7), 100; https://doi.org/10.3390/sports8070100 - 14 Jul 2020
Cited by 28 | Viewed by 9989
Abstract
The ongoing global pandemic brought about by Coronavirus II (SARS-Cov-2 or COVID-19) has caused an ongoing cessation of sporting competitions and training facility closures. This is a fundamental challenge for amateur and elite sporting professionals. Although recommendations have been provided for team-sport athletes [...] Read more.
The ongoing global pandemic brought about by Coronavirus II (SARS-Cov-2 or COVID-19) has caused an ongoing cessation of sporting competitions and training facility closures. This is a fundamental challenge for amateur and elite sporting professionals. Although recommendations have been provided for team-sport athletes to maintain general and sport-specific conditioning, these methods are often not optimal for strength athletes (i.e., powerlifting (PL) and weightlifting (WL)) due to the unique and narrow set of performance requirements posed by these sports. The purpose of this review is to provide evidence-based information and recommendations and highlight potential strategies and approaches that may be used by strength (PL and WL) athletes during the current global crisis. Collectively, we provide evidence from resistance training literature regarding the loss of muscle strength, power and mass, minimum training frequencies required to attenuate such losses and training re-adaptation. Additionally, we suggest that time off training and competition caused by ongoing restrictions may be used for other purposes, such as overcoming injury and improving movement quality and/or mobility, goal setting, psychological development and emphasizing strength sports for health. These suggestions are intended to be useful for coaches, strength athletes and organizations where existing training strategies and recommendations are not suitable or no longer feasible. Full article
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12 pages, 3508 KiB  
Discussion
Effect of ACTN3 Genotype on Sports Performance, Exercise-Induced Muscle Damage, and Injury Epidemiology
by Gabriel Baltazar-Martins, Jorge Gutiérrez-Hellín, Millán Aguilar-Navarro, Carlos Ruiz-Moreno, Victor Moreno-Pérez, Álvaro López-Samanes, Raúl Domínguez and Juan Del Coso
Sports 2020, 8(7), 99; https://doi.org/10.3390/sports8070099 - 13 Jul 2020
Cited by 16 | Viewed by 9904
Abstract
Genetic factors play a significant role in athletic performance and its related phenotypes such as power, strength and aerobic capacity. In this regard, the lack of a muscle protein due to a genetic polymorphism has been found to affect sport performance in a [...] Read more.
Genetic factors play a significant role in athletic performance and its related phenotypes such as power, strength and aerobic capacity. In this regard, the lack of a muscle protein due to a genetic polymorphism has been found to affect sport performance in a wide variety of ways. α-actinin-3 is a protein located within the skeletal muscle with a key role in the production of sarcomeric force. A common stop-codon polymorphism (rs1815739; R577X) in the gene that codes for α-actinin-3 (ACTN3) produces individuals with the XX genotype that lack expression of a functional α-actinin-3. In contrast, individuals with the R-allele (i.e., RX vs. RR genotypes) in this polymorphism can express α-actinin-3. Interestingly, around ~18% of the world population have the XX genotype and much has been debated about why a polymorphism that produces a lack of a muscle protein has endured natural selection. Several investigations have found that α-actinin-3 deficiency due to XX homozygosity in the ACTN3 R577X polymorphism can negatively affect sports performance through several structural, metabolic, or signaling changes. In addition, new evidence suggests that α-actinin-3 deficiency may also impact sports performance through indirect factors such a higher risk for injury or lower resistance to muscle-damaging exercise. The purpose of this discussion is to provide a clear explanation of the effect of α-actinin-3 deficiency due to the ACTN3 XX genotype on sport. Key focus has been provided about the effect of α-actinin-3 deficiency on morphologic changes in skeletal muscle, on the low frequency of XX athletes in some athletic disciplines, and on injury epidemiology. Full article
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13 pages, 1244 KiB  
Article
A Thirty-Five-Minute Nap Improves Performance and Attention in the 5-m Shuttle Run Test during and outside Ramadan Observance
by Hsen Hsouna, Omar Boukhris, Khaled Trabelsi, Raouf Abdessalem, Achraf Ammar, Jordan M. Glenn, Nick Bott, Nizar Souissi, Paola Lanteri, Sergio Garbarino, Nicola Luigi Bragazzi and Hamdi Chtourou
Sports 2020, 8(7), 98; https://doi.org/10.3390/sports8070098 - 11 Jul 2020
Cited by 13 | Viewed by 2947
Abstract
Ramadan observance is characterized by several changes in behaviors, such as food and sleep, which could affect physical and cognitive performance. The aim of the present study was to investigate the effects of a 35-min nap (N35) opportunity on physical performance during the [...] Read more.
Ramadan observance is characterized by several changes in behaviors, such as food and sleep, which could affect physical and cognitive performance. The aim of the present study was to investigate the effects of a 35-min nap (N35) opportunity on physical performance during the 5-m shuttle run test (5mSRT); attention; feelings; mood states; and perceptual measures of stress, fatigue, and muscle soreness during Ramadan observance. Fourteen physically active men (22 ± 3 years, 177 ± 4 cm, 76 ± 5 kg) were tested after a no-nap condition (N0), N35 15 days before Ramadan (BR), the last 10 days of Ramadan (DR), and 20 days after Ramadan (AR). Measures included the digit cancellation test (attention estimation), the profile of mood state (POMS), and the Hooper questionnaires. After a 5-min standard warm-up, participants performed the 5mSRT (6 × 30 s with 35 s in between; best distance (BD), total distance (TD), and fatigue index (FI) were recorded), along with the rating of perceived exertion (RPE) after each test repetition. After the 5mSRT test, participants responded to the feeling scale (FS). The results showed that TD and FI during the 5mSRT were not affected by Ramadan observance. However, BD was significantly lower than DR compared to AR after N0 (∆ = −4.3 ± 1.3%; p < 0.01) and N35 (∆ = −2.6 ± 1.0%; p < 0.05). After N0, attention decreased significantly at DR in comparison with BR (p < 0.05) and AR (p < 0.001). BD and TD improved after N35 compared to N0 at BR (∆ = +4.4 ± 2.1%, p < 0.05 for BD and ∆ = +4.8 ± 1.6%, p < 0.01 for TD), DR (∆ = +7.1 ± 2.2%, p < 0.05 for BD and ∆ = +5.1 ± 1.6%, p < 0.01 for TD), and AR (∆ = +5.5 ± 1.5%, p < 0.01 for BD and ∆ = +5.2 ± 1.2%, p < 0.001 for TD). A significant increase in attention was observed after N35 in comparison with N0 at DR (p < 0.01) and AR (p < 0.01). However, no changes were found for the perception of mood states, stress, sleep, muscle soreness, and the FI during the 5mSRT. Also, N35 was better than N0 for RPE at DR (p < 0.05), feelings at AR (p < 0.05), and fatigue estimation at AR (p < 0.01). A 35-min nap opportunity may have beneficial effects on physical and cognitive performances before, during, and after Ramadan. Full article
(This article belongs to the Special Issue Psychophysiological Response in Sports)
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16 pages, 1059 KiB  
Article
Evolution of Physical Fitness in Formative Female Basketball Players: A Case Study
by David Mancha-Triguero, Nicolás Martín-Encinas and Sergio J. Ibáñez
Sports 2020, 8(7), 97; https://doi.org/10.3390/sports8070097 - 08 Jul 2020
Cited by 7 | Viewed by 2750
Abstract
Over the last few years, team sports increased the amount of physical demand and its importance. Therefore, work related to physical fitness and its assessment is essential to achieving success. However, there are few studies on this subject at the formative stage. The [...] Read more.
Over the last few years, team sports increased the amount of physical demand and its importance. Therefore, work related to physical fitness and its assessment is essential to achieving success. However, there are few studies on this subject at the formative stage. The purpose of this study was then to analyze the physical fitness of an under-18 (U18) women’s team divided by game positions. In addition, physical fitness at different times of the season was characterized to identify differences and determine its evolution. To assess physical fitness, tests of aerobic and anaerobic capacities, lower body strength, centripetal force, agility and speed were carried out as designed in the SBAFIT battery. Each player was equipped with an inertial microtechnology device for the collection of data. This research is classified as empirical, with quasi-experimental methodology. The results showed significant differences in variables of the test of aerobic and anaerobic capacities, speed, agility (generic and specific), and centripetal force (right) based on game position and the moment of the season. The results also showed the importance of the specific physical aspect in relation to an optimal improvement in physical fitness, since training sessions and competition do not allow all players to improve equally or efficiently. Full article
(This article belongs to the Special Issue Physical Performance in Team Sports)
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11 pages, 865 KiB  
Article
Sociodemographic Determinants of Physical Activity and Sport Participation among Women in the United States
by Jennifer R. Pharr, Nancy L. Lough and Angela M. Terencio
Sports 2020, 8(7), 96; https://doi.org/10.3390/sports8070096 - 02 Jul 2020
Cited by 13 | Viewed by 3738
Abstract
Regular physical activity and sport participation have been shown to improve women’s health; however, research has found that better health is associated with sport participation. Little is known about the sociodemographic determinants of physical activity among women, especially among the different subcategories of [...] Read more.
Regular physical activity and sport participation have been shown to improve women’s health; however, research has found that better health is associated with sport participation. Little is known about the sociodemographic determinants of physical activity among women, especially among the different subcategories of physical activity (sport, conditioning exercise, recreation, and household tasks). Because of the added health benefits associated with sport participation, the purpose of this study was to examine the sociodemographic determinants among subcategories of physically active women in the United States by analyzing Behavioral Risk Factor Surveillance System (BRFSS) data. We used data from the 2017 national BRFSS survey to conduct this secondary data analysis. Participants were asked an extensive set of questions about their physical activity. Seventy-six different activities were identified and categorized as either sport, recreation, conditioning exercise, or household tasks. Weighted descriptive statistics were performed to describe the sociodemographic determinants of the four physical activity subcategories, including age, income, education, employment, and race/ethnicity. There were significant differences in all sociodemographic variables among the four subcategories of physical activity. Women who participated in sport were more likely to be in the younger age groups; however, physical activity declined among all subcategories beyond the age of 64. Women who participated in sports were more diverse, likely to be employed, and college graduates compared to the other subcategories. Women who participated in recreational or household tasks were more likely to meet the criteria to be categorized as highly active; however, they exercised at a lower intensity. The sociodemographic characteristics of physical activity and sport participation can be used to create promotional strategies to increase physical activity and improve fitness and health among women who tend towards participation, and also to change programs to accommodate women from other sociodemographic groups. Full article
(This article belongs to the Special Issue Intersection of Sport, Physical Activity and Human Health)
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10 pages, 788 KiB  
Article
Verifying Physiological and Biomechanical Parameters during Continuous Swimming at Speed Corresponding to Lactate Threshold
by Gavriil G. Arsoniadis, Ioannis S. Nikitakis, Petros G. Botonis, Ioannis Malliaros and Argyris G. Toubekis
Sports 2020, 8(7), 95; https://doi.org/10.3390/sports8070095 - 30 Jun 2020
Cited by 2 | Viewed by 3748
Abstract
The purpose of this study was to verify the physiological responses and biomechanical parameters measured during 30 min of continuous swimming (T30) at intensity corresponding to lactate threshold previously calculated by an intermittent progressively increasing speed test (7 × 200 m). Fourteen competitive [...] Read more.
The purpose of this study was to verify the physiological responses and biomechanical parameters measured during 30 min of continuous swimming (T30) at intensity corresponding to lactate threshold previously calculated by an intermittent progressively increasing speed test (7 × 200 m). Fourteen competitive swimmers (18.0 (2.5) years, 67.5 (8.8) kg, 174.5 (7.7) cm) performed a 7 × 200 m front crawl test. Blood lactate concentration (BL) and oxygen uptake (VO2) were determined after each 200 m repetition, while heart rate (HR), arm-stroke rate (SR), and arm-stroke length (SL) were measured during each 200 m repetition. Using the speed vs. lactate concentration curve, the speed at lactate threshold (sLT) and parameters corresponding to sLT were calculated (BL-sLT, VO2-sLT, HR-sLT, SR-sLT, and SL-sLT). In the following day, a T30 corresponding to sLT was performed and BL-T30, VO2-T30, HR-T30, SR-T30, and SL-T30 were measured after the 10th and 30th minute, and average values were used for comparison. VO2-sLT was no different compared to VO2-T30 (p > 0.05). BL-T30, HR-T30, and SR-T30 were higher, while SL-T30 was lower compared to BL-sLT, HR-sLT, SR-sLT, and SL-sLT (p < 0.05). Continuous swimming at speed corresponding to lactate threshold may not show the same physiological and biomechanical responses as those calculated by a progressively increasing speed test of 7 × 200 m. Full article
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19 pages, 2558 KiB  
Article
The Reliability and Validity of Current Technologies for Measuring Barbell Velocity in the Free-Weight Back Squat and Power Clean
by Steve W. Thompson, David Rogerson, Harry F. Dorrell, Alan Ruddock and Andrew Barnes
Sports 2020, 8(7), 94; https://doi.org/10.3390/sports8070094 - 30 Jun 2020
Cited by 44 | Viewed by 8772
Abstract
This study investigated the inter-day and intra-device reliability, and criterion validity of six devices for measuring barbell velocity in the free-weight back squat and power clean. In total, 10 competitive weightlifters completed an initial one repetition maximum (1RM) assessment followed by three load-velocity [...] Read more.
This study investigated the inter-day and intra-device reliability, and criterion validity of six devices for measuring barbell velocity in the free-weight back squat and power clean. In total, 10 competitive weightlifters completed an initial one repetition maximum (1RM) assessment followed by three load-velocity profiles (40–100% 1RM) in both exercises on four separate occasions. Mean and peak velocity was measured simultaneously on each device and compared to 3D motion capture for all repetitions. Reliability was assessed via coefficient of variation (CV) and typical error (TE). Least products regression (LPR) (R2) and limits of agreement (LOA) assessed the validity of the devices. The Gymaware was the most reliable for both exercises (CV < 10%; TE < 0.11 m·s−1, except 100% 1RM (mean velocity) and 90‒100% 1RM (peak velocity)), with MyLift and PUSH following a similar trend. Poorer reliability was observed for Beast Sensor and Bar Sensei (CV = 5.1–119.9%; TE = 0.08–0.48 m·s−1). The Gymaware was the most valid device, with small systematic bias and no proportional or fixed bias evident across both exercises (R2 > 0.42–0.99 LOA = −0.03–0.03 m·s−1). Comparable validity data was observed for MyLift in the back squat. Both PUSH devices produced some fixed and proportional bias, with Beast Sensor and Bar Sensei being the least valid devices across both exercises (R2 > 0.00–0.96, LOA = −0.36–0.46 m·s−1). Linear position transducers and smartphone applications could be used to obtain velocity-based data, with inertial measurement units demonstrating poorer reliability and validity. Full article
(This article belongs to the Special Issue New Perspectives in Resistance Training)
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12 pages, 1313 KiB  
Article
Validation of Inertial Sensor to Measure Barbell Kinematics across a Spectrum of Loading Conditions
by John C. Abbott, John P. Wagle, Kimitake Sato, Keith Painter, Thaddeus J. Light and Michael H. Stone
Sports 2020, 8(7), 93; https://doi.org/10.3390/sports8070093 - 29 Jun 2020
Cited by 13 | Viewed by 2535
Abstract
The aim of this study was to evaluate the level of agreement in measuring back squat kinematics between an inertial measurement unit (IMU) and a 3D motion capture system (3DMOCAP). Kinematic variables included concentric peak velocity (CPV), concentric mean velocity (CMV), eccentric peak [...] Read more.
The aim of this study was to evaluate the level of agreement in measuring back squat kinematics between an inertial measurement unit (IMU) and a 3D motion capture system (3DMOCAP). Kinematic variables included concentric peak velocity (CPV), concentric mean velocity (CMV), eccentric peak velocity (EPV), eccentric mean velocity (EMV), mean propulsive velocity (MPV), and POP-100: a proprietary variable. Sixteen resistance-trained males performed an incrementally loaded one repetition maximum (1RM) squat protocol. A series of Pearson correlations, 2 × 4 RM ANOVA, Cohen’s d effect size differences, coefficient of variation (CV), and standard error of the estimate (SEE) were calculated. A large relationship existed for all variables between devices (r = 0.78–0.95). Between-device agreement for CPV worsened beyond 60% 1RM. The remaining variables were in agreement between devices with trivial effect size differences and similar CV magnitudes. These results support the use of the IMU, regardless of relative intensity, when measuring EMV, EPV, MPV, and POP-100. However, practitioners should carefully select kinematic variables of interest when using the present IMU device for velocity-based training (VBT), as certain measurements (e.g., CMV, CPV) do not possess practically acceptable reliability or accuracy. Finally, the IMU device exhibited considerable practical data collection concerns, as one participant was completely excluded and 13% of the remaining attempts displayed obvious internal error. Full article
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12 pages, 800 KiB  
Article
Physiological Predictors of Performance on the CrossFit “Murph” Challenge
by Ja’Deon D. Carreker and Gregory J. Grosicki
Sports 2020, 8(7), 92; https://doi.org/10.3390/sports8070092 - 28 Jun 2020
Cited by 17 | Viewed by 4653
Abstract
We examined physiological predictors of performance on the CrossFit Murph challenge (1-mile run, 100 pullups, 200 pushups, 300 air squats, 1-mile run). Male CrossFit athletes (n = 11, 27 ± 3 years) performed a battery of physical assessments including: (1) body composition, [...] Read more.
We examined physiological predictors of performance on the CrossFit Murph challenge (1-mile run, 100 pullups, 200 pushups, 300 air squats, 1-mile run). Male CrossFit athletes (n = 11, 27 ± 3 years) performed a battery of physical assessments including: (1) body composition, (2) upper and lower body strength, (3) upper body endurance, (4) anaerobic power, and (5) maximal oxygen consumption. No less than 72 h later, participants completed the Murph challenge, heart rate was monitored throughout, and blood lactate was obtained pre-post. Correlations between physiological parameters and total Murph time, and Murph subcomponents, were assessed using Pearson’s correlations. Murph completion time was 43.43 ± 4.63 min, and maximum and average heart rate values were 185.63 ± 7.64 bpm and 168.81 ± 6.41 bpm, respectively, and post-Murph blood lactate was 10.01 ± 3.04 mmol/L. Body fat percentage was the only physiological parameter significantly related to total Murph time (r = 0.718; p = 0.013). Total lift time (25.49 ± 3.65 min) was more strongly related (r = 0.88) to Murph time than total run time (17.60 ± 1.97 min; r = 0.65). Greater relative anaerobic power (r = −0.634) and less anaerobic fatigue (r = 0.649) were related to total run time (p < 0.05). Individuals wanting to enhance overall Murph performance are advised to focus on minimizing body fat percentage and improving lift performance. Meanwhile, performance on the run subcomponent may be optimized through improvements in anaerobic power. Full article
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14 pages, 250 KiB  
Article
Effects of Plyometric and Repeated Sprint Training on Physical Performance
by Ivan Krakan, Luka Milanovic and Ivan Belcic
Sports 2020, 8(7), 91; https://doi.org/10.3390/sports8070091 - 27 Jun 2020
Cited by 5 | Viewed by 3179
Abstract
The purpose of study was to resolve the effect of plyometric training and repeated sprint training on physical performance. The study was conducted on 41 subjects in two experimental groups (plyometric/repeated sprints training). Before and after the training program, subjects were subjected to [...] Read more.
The purpose of study was to resolve the effect of plyometric training and repeated sprint training on physical performance. The study was conducted on 41 subjects in two experimental groups (plyometric/repeated sprints training). Before and after the training program, subjects were subjected to diagnostic procedures that included standard test protocols. Results proved a statistically significant difference only after the plyometric training program compared to the repeated sprint group in countermovement jump (8.65% vs. 2.21%). In variable repeated jumps, an increased value was recorded (2.9% vs. 4.29%), like in sprint variables after the training program where certain trends of progress happened after the repeated sprint ability training and the specificity of the program (5 m = 0.89%, 10 m = 1.07% and 25 m = 1.35%), while plyometric training recorded unchanged values at 5 and 10 m, and a 0.27% improvement at 25 m. Stagnation of the 20-yard test was recorded in both groups. There was no difference between training programs in any variables of functional capacities, with similar measures recorded in repeated sprint ability. After six weeks of both training types, positive changes can be expected in explosive strength of lower extremities, increases in acceleration area, and maximum speed. Full article
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