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Sports teams have at their disposal a vast array of wearable technology to assist in monitoring training loads and to assess rehabilitation. In particular, global positioning (GPS) and accelerometry have been incorporated into devices that can be positioned at different locations in the body (e.g. trunk, wrist, ankle and foot). With access to multiple devices and different analysis platforms, can multiple devices provide more insight into athlete monitoring? Are we measuring different things or simply exploring redundancies?

There are few return-to-activity protocols and functional tests specifically designed for a proximal hamstring rupture for athletic trainers to follow when clearing an athlete for return to activity. To address this problem, the purpose of this study is to describe and evaluate a return to activity protocol that includes functional testing for a post-surgical proximal hamstring rupture to assess readiness for return to activity. This case study collected data from a 20-year-old, 6ft 2in, 185lb (87.9 kg) collegiate heptathlete that ruptured his proximal hamstring that required surgical treatment. The student athlete’s (SA) return to activity process is evaluated and explained. The SA went through numerous function tests to determine return to activity status. The first testing session was conducted 8 months post-surgery. He was then re-assessed 4 months later. During testing, the SA also wore accelerometers to gather more quantitative data to identify gait abnormalities due to the injury. The first round of testing revealed greater strength in his left (affected) leg compared to his right (unaffected) leg. The SA was not able to complete all the tests during the first round of testing due to muscular fatigue and soreness, suggesting low muscular endurance at that point in time. Thus, he was not cleared to return to activity and continued to do rehabilitation exercises to increase the endurance of the hamstring muscles. The second round of testing was completed 4 months later which revealed that he had gained endurance in the hamstring muscles and his strength had increased. At this point, he was cleared for full return to activity. This return-to-activity protocol with specific functional tests could serve as a template for other athletic trainers who are seeking to return an athlete to full activity after suffering a proximal hamstring rupture (See Appendix I).

In the companion study, we report a new approach for analyzing gait complexity and the structure of gait variability (12). Previous studies show that the fractal scaling index (FSI) determined using detrended uctuation analysis (DFA) is reduced by neuromuscular disorders (6) as well as low back pain, fatigue, injury and overtraining (2, 5, 8, 10), indicating a less healthy gait (1). On the other hand, physical training increases DFA (9).

The purpose of this study was to determine the accuracy of distance measurements obtained using a Fitbit device compared to a highly accurate GPS-embedded accelerometer device. The participants of this study completed two, 18-hole rounds of golf on two different courses. Prior to each round, participants were fitted with Fitbit device worn on the wrist and a GPSports device secured to the lower back. The participants were eight student-athletes on the Virginia Tech Women’s golf team who completed the quantitative case study that assessed the accuracy of the Fitbit devices. The objective of this project was to provide those who play golf with a better understanding on whether or not a Fitbit can be trusted to provide accurate results when competing in a round of 18 holes of golf. A t-test was used to analyze the data once collected. Results of this study show signs that the Fitbit underestimates the distance traveled when compared with the GPS device. For future research we recommend using more specific ranges when comparing the two devices rather than just the two separate 18 hole rounds.

The validity and reliability of global positioning technology (GPS) for measuring the physical demands of various sports have been questioned (1,2,3). Court-based sports are characterized by rapid changes in direction within a confined space (4,5,6,7). Thus, one would expect lower quality of GPS data compared to eld sports (8,9,10).

The validity and reliability of global positioning technology (GPS) for measuring the physical demands of various sports have been questioned (1,2,3). Court-based sports are characterized by rapid changes in direction within a confined space (4,5,6,7). Thus, one would expect lower quality of GPS data compared to eld sports (8,9,10).

The goal of this investigation was to determine if playing or training on third-generation artificial turf (AT) surfaces increases the incidence rate of injuries compared to natural grass (NG) surfaces. This was accomplished by a meta-analysis performed on previously published research. Eight studies met the criteria of competitive soccer players, participation on both surfaces, and presentation of both exposure time and injury occurrence. Exposure time and injury incidence values were used to generate injury rate ratios (IRRs, AT/NG) for all injuries as well as specific injuries. Subgroup analyses were also performed by condition (match or training), gender, and age (youth or adult). The overall IRR was 0.86 (P < 0.05) suggesting a lower injury risk on AT than NG. However, there was considerable heterogeneity between studies. Analyses of individual injuries and subgroups found that in many cases IRR values were significantly less than 1.0. In no case was the IRR significantly greater than 1.0. Based on this, it appears that the risk of sustaining an injury on AT under some conditions might be lowered compared to NG. However, until more is known about how issues such as altered playing styles affect injury incidence, it is difficult to make firm conclusions regarding the influence of AT on player safety.

The goal of this investigation was to determine if playing or training on third-generation artificial turf (AT) surfaces increases the incidence rate of injuries compared to natural grass (NG) surfaces. This was accomplished by a meta-analysis performed on previously published research. Eight studies met the criteria of competitive soccer players, participation on both surfaces, and presentation of both exposure time and injury occurrence. Exposure time and injury incidence values were used to generate injury rate ratios (IRRs, AT/NG) for all injuries as well as specific injuries. Subgroup analyses were also performed by condition (match or training), gender, and age (youth or adult). The overall IRR was 0.86 (P < 0.05) suggesting a lower injury risk on AT than NG. However, there was considerable heterogeneity between studies. Analyses of individual injuries and subgroups found that in many cases IRR values were significantly less than 1.0. In no case was the IRR significantly greater than 1.0. Based on this, it appears that the risk of sustaining an injury on AT under some conditions might be lowered compared to NG. However, until more is known about how issues such as altered playing styles affect injury incidence, it is difficult to make firm conclusions regarding the influence of AT on player safety.

This investigation examined the effects of reduced muscle glycogen on exercise performance and muscle fatigue. Male rats were assigned to a low glycogen group (LG) that participated in a protocol of exercise and fasting, a high glycogen group (HG) that exercised but were allowed free access to food, or control group (CON) that did not exercise but were allowed free access to food. Following the protocol, muscle glycogen content of the LG animals was reduced by 45%. The LG animals also performed 79 and 81% less voluntary treadmill exercise than the HG and CON groups. At exhaustion, the LG group had lower blood glucose than HG and CON but exhibited no reduction in sarcoplasmic reticulum (SR) function. During 30 min of in situ stimulation, the rates and magnitudes of muscle fatigue were not significantly different between groups, and fatigue-induced reductions in SR function were similar between groups. The results indicate that reduced muscle glycogen markedly impairs voluntary exercise performance but does not appreciably affect isolated muscle function. It is likely that exercise exhaustion due to reduced muscle glycogen is due, in large part, to hypoglycemia and central fatigue as opposed to peripheral mechanisms.

This investigation examined the effects of reduced muscle glycogen on exercise performance and muscle fatigue. Male rats were assigned to a low glycogen group (LG) that participated in a protocol of exercise and fasting, a high glycogen group (HG) that exercised but were allowed free access to food, or control group (CON) that did not exercise but were allowed free access to food. Following the protocol, muscle glycogen content of the LG animals was reduced by 45%. The LG animals also performed 79 and 81% less voluntary treadmill exercise than the HG and CON groups. At exhaustion, the LG group had lower blood glucose than HG and CON but exhibited no reduction in sarcoplasmic reticulum (SR) function. During 30 min of in situ stimulation, the rates and magnitudes of muscle fatigue were not significantly different between groups, and fatigue-induced reductions in SR function were similar between groups. The results indicate that reduced muscle glycogen markedly impairs voluntary exercise performance but does not appreciably affect isolated muscle function. It is likely that exercise exhaustion due to reduced muscle glycogen is due, in large part, to hypoglycemia and central fatigue as opposed to peripheral mechanisms.

Background Late stage cancer malignancies may result in severe skeletal muscle wasting, fatigue and reduced quality of life. Resistance training may attenuate these derangements in cancer patients, but how this hypertrophic response relates to normal muscle adaptations in healthy subjects is unknown. Here, we determined the effect of resistance training on muscle mass and myosin heavy chain (MHC) isoform composition in plantaris muscles from tumor-bearing (TB) rats. Methods Age- and gender-matched Buffalo rats were used for all studies (n = 6/group). Suspensions of Morris Hepatoma MH7777 cells or normal saline were injected subcutaneously into the dorsum. Six weeks after cell implantation, muscles from TB rats were harvested, weighed and processed for ATP-independent proteasome activity assays. Once tumor-induced atrophy had been established, subgroups of TB rats underwent unilateral, functional overload (FO). Healthy, sham-operated rats served as controls. After six weeks, the extent of plantaris hypertrophy was calculated and MHC isoform compositions were determined by gel electrophoresis. Results Six weeks of tumor growth reduced body mass and the relative masses of gastrocnemius, plantaris, tibialis anterior, extensor digitorum longus, and diaphragm muscles (p ≤ 0.05). Percent reductions in body mass had a strong, negative correlation to final tumor size (r = -0.78). ATP-independent proteasome activity was increased in plantaris muscles from TB rats (p ≤ 0.05). In healthy rats, functional overload (FO) increased plantaris mass ~44% compared to the contralateral control muscle, and increased the relative percentage of MHC type I and decreased the relative percentage of MHC type IIb compared to the sham-operated controls (p ≤ 0.05). Importantly, plantaris mass was increased ~24% in TB-FO rats and adaptations to MHC isoform composition were consistent with normal, resistance-trained muscles. Conclusion Despite significant skeletal muscle derangements due to cancer

Background Late stage cancer malignancies may result in severe skeletal muscle wasting, fatigue and reduced quality of life. Resistance training may attenuate these derangements in cancer patients, but how this hypertrophic response relates to normal muscle adaptations in healthy subjects is unknown. Here, we determined the effect of resistance training on muscle mass and myosin heavy chain (MHC) isoform composition in plantaris muscles from tumor-bearing (TB) rats. Methods Age- and gender-matched Buffalo rats were used for all studies (n = 6/group). Suspensions of Morris Hepatoma MH7777 cells or normal saline were injected subcutaneously into the dorsum. Six weeks after cell implantation, muscles from TB rats were harvested, weighed and processed for ATP-independent proteasome activity assays. Once tumor-induced atrophy had been established, subgroups of TB rats underwent unilateral, functional overload (FO). Healthy, sham-operated rats served as controls. After six weeks, the extent of plantaris hypertrophy was calculated and MHC isoform compositions were determined by gel electrophoresis. Results Six weeks of tumor growth reduced body mass and the relative masses of gastrocnemius, plantaris, tibialis anterior, extensor digitorum longus, and diaphragm muscles (p ≤ 0.05). Percent reductions in body mass had a strong, negative correlation to final tumor size (r = -0.78). ATP-independent proteasome activity was increased in plantaris muscles from TB rats (p ≤ 0.05). In healthy rats, functional overload (FO) increased plantaris mass ~44% compared to the contralateral control muscle, and increased the relative percentage of MHC type I and decreased the relative percentage of MHC type IIb compared to the sham-operated controls (p ≤ 0.05). Importantly, plantaris mass was increased ~24% in TB-FO rats and adaptations to MHC isoform composition were consistent with normal, resistance-trained muscles. Conclusion Despite significant skeletal muscle derangements due to cancer