Changes in Creatine Kinase and Hormones Over the Course of an American Football Season

Effect of Ginseng Supplementation on Exercise Endurance as a Support for Cardiovascular Disease Management: A Systematic Review and Meta-Analysis

Ginseng has multi-directional pharmacological properties. Some data suggest that ginseng can enhance physical endurance, which, in turn, leads to protection of the cardiovascular system. However, not all experiments are conclusive. For this reason, the main aim of this research was to perform a meta-analysis and review of studies published between the years 2013 and 2023 concerning the ginseng effect on physical performance in animal and human models. Medline, Pubmed, and ClinicalKey electronic databases were used to analyze data. The search strategy included the following criteria: ginseng and exercise; ginseng supplementation; and ginseng supplements. The results suggest that ginseng supplementation may have a positive effect on CK levels in animal studies. Similar observations were stated in relation to serum lactate and BUN. Furthermore, a human study showed a significant increase in exercise time to exhaustion and VO2 max after supplementation. The review of the literature and conducted meta-analysis identified that ginseng supplementation may have a positive effect on exercise endurance. Due to the fact that most of the current studies were based on animal models, further research on human models is needed to identify the most effective dosage or form of applied ginseng to be a supportive element in CVD management.

Anabolic/Catabolic Hormone Imbalance but Still Jumping Further? Negative Association of Free Testosterone With Jumping Performance in Elite Handball Players Following a Preparatory Period

Purpose: The present study investigated the effects of a 10-week preparatory training period on biomarkers and jumping performance and associations of changes in biomarkers, load, and jumping performance from the beginning (PRE) to the end of the preparatory period (POST) in elite handball players. Methods: Seventeen elite handball players competing in the first Slovenian men's League were recruited. Training, competition and academic loads were reported weekly, while biomarkers and jumping performance were assessed at PRE and POST. Results: At POST, decreased levels of free testosterone (large effect size [ES] = -1.69, p < .001) and free testosterone to cortisol ratio [FTCR] (large ES = -.95, p = .004) were observed; whereas, better performance on the single leg lateral hop test [SLLH] (large ES = .85, p = .007) and single leg triple hop test [SLTH] (large ES = 1.05, p = .002) were observed compared to PRE. Furthermore, changes in FTCR correlated with changes in cortisol (high r = -.751, p = .001), SLLH (moderate r = -.603, p = .022), and SLTH (moderate r = -.643, p = .013), while changes in free testosterone correlated with SLTH (moderate r = -.645, p = .013). Conclusions: High intensity trainings with a saturated competition schedule can result in disturbed anabolic/catabolic hormone ratio observed through FTCR decrease, which could indicate either an optimal state or early exhaustiveness. It seems that SLLH and SLTH are more sensitive to changes in biomarkers than a single leg hop test. Sport professionals may use the results for individualized monitoring of an athlete's health and performance, specifically, as an aid for adjusting training loads accordingly to prevent performance declines and potential injury/illness events.

Effects of COVID-19 on Rate of Injury and Position-Specific Injury During the 2020 National Football League Season

ABSTRACT

Costello II, JP, Wagner, JD, Dahl, VA, Cohen, JL, Reuter, AM, and Kaplan, LD. Effects of COVID-19 on rate of injury and position-specific injury during the 2020 National Football League season. J Strength Cond Res 38(1): 97-104, 2024-Because of the COVID-19 pandemic, the National Football League (NFL) made changes to its operations for the 2020 season. We hypothesize an increase in the rate of injuries during the 2020 season. Publicly available data were reviewed to identify NFL injuries from the 2015-2020 seasons. Player position, description of injury, date of injury, and injury setting were recorded. p ≤ 0.05 was considered statistically significant. For the 2020 season, compared with the 2015-2019 seasons, there was an increased risk of injury during the regular season overall relative risk (RR) = 1.308 ( p < 0.05), week (W)1 RR = 7.33 ( p < 0.05), W1-6 RR = 1.964 ( p < 0.05), W7-12 RR = 1.8909 ( p < 0.05), and during the postseason overall RR = 1.1444 ( p < 0.05), calculated using analysis of variance. There was an overall increased risk of abdominal or core injuries RR = 1.248 ( p < 0.05), groin or hip injuries RR = 2.534 ( p < 0.05), and hamstring injuries RR = 3.644 ( p < 0.05). There was an increased risk of hamstring injuries in cornerbacks RR = 3.219 ( p < 0.05) and running backs RR = 1.1394 ( p < 0.05), hip or groin injuries in guards RR = 1.105 ( p < 0.05), Achilles tendon injuries in safeties RR = 1.6976 ( p < 0.05), quadriceps injuries in running backs RR = 1.6191 ( p < 0.05), and arm injuries in defensive tackles RR = 1.221 ( p < 0.05). There was an increase in the overall rate of injuries in the 2020 NFL season, both in the regular season and postseason, compared with the 2015-2019 seasons. The overall rate of abdominal or core, groin or hip, and hamstring injuries increased. Specific player positions saw unique increases in rates of injuries. These findings may be due to numerous operational changes implemented, such as reduced in-person training and the elimination of the preseason, leading to suboptimal, sports-specific conditioning and increased risk of musculoskeletal injury.

Acute Effects of Training Loads on Muscle Damage Markers and Performance in Semi-elite and Elite Athletes: A Systematic Review and Meta-analysis

BACKGROUND

The relationship between exercise-induced muscle damage (EIMD) indicators and acute training loads (TL) is yet to be reviewed extensively in semi-elite and elite athlete populations.

OBJECTIVES

The objectives of this systematic review and meta-analysis were threefold: (1) to evaluate studies of EIMD following the initial period of the preseason in semi-elite and elite athletes: (2) to examine acute physiological and performance responses across two periods of the season with similar TL; and (3) to examine acute physiological and performance responses to acute changes in TL during the season.

METHODS

The CINAHL, PubMed, Scopus, SPORTDiscus and Web of Science databases were systematically searched for studies that investigated: (1) semi-elite or elite athletes in team or individual sports following a periodised training programme; and (2) measured acute responses to training. Studies were excluded if: (1) conducted in animals; (2) non-English language; or (3) a conference abstract, review or case report. The Kmet Quality Scoring of Quantitative Studies tool was used for study appraisal.

SYNTHESIS METHODS

Data were quantitatively analysed by generating forest plots to report test statistics for statistical significance and inter-trial heterogeneity.

RESULTS

Of the included studies (n = 32), athletes experienced greater creatine kinase (CK) concentrations (Z = 4.99, p < 0.00001, I² = 74%), inflammatory factors and other indirect measures of muscle damage in the initial phase of the preseason period compared to the off-season; there were no changes in CK (Z = 1.43, p = 0.15, I² = 74%) across two time points of similar TL; and there were concurrent increases in CK with increases in TL (Z = 4.26, p < 0.0001, I² = 36%) and vice versa (Z = 4.33, p < 0.0001, I² = 79%).The qualitative analysis identified that the response of inflammatory factors and other indirect measures of muscle damage to changes in load were inconclusive.

LIMITATIONS

This review included varying age, sex, sports and competition levels. The group level meta-analysis failed to identify within-athlete or position-specific differences across time.

CONCLUSION

Blood biomarkers of EIMD may not differ across periods of similar TL, however can be considered a sensitive monitoring tool for assessing responses following acute TL changes in semi-elite and elite athletes.

Neuromuscular, Endocrine, and Perceptual Recovery After a Youth American Football Game

ABSTRACT

Davis, JK, Wolfe, AS, Basham, SA, Freese, EC, and De Chavez, PJD. Neuromuscular, endocrine, and perceptual recovery after a youth American football game. J Strength Cond Res 35(5): 1317-1325, 2021-American football is a high-intensity intermittent sport consisting of various movements and repeated collisions which highlights the importance of adequate recovery from a game to prepare for the next competition. Therefore, the purpose of this study was to determine the time course of recovery markers after a youth American football game. Thirteen male American football youth players were monitored for 7 days after a single football game. Baseline measures were taken 28 hours pregame for lower-body neuromuscular function by countermovement jumps (CMJs) to determine peak power (PP), jump height (JH), flight time (FT), and takeoff velocity (TOV). Saliva was analyzed for cortisol, testosterone, and C-reactive protein (CRP). Perceptual recovery was assessed by the modified profile of mood states (POMS), perceived recovery status (PRS), and a daily wellness questionnaire. These measures were repeated immediately postgame (30 minutes) and at 20, 44, 68, 92, 116, and 140 hours postgame. Compared with baseline values, there was a significant decrease (p < 0.05) in CMJ PP, JH, and TOV up to 68 hours postgame and FT 44 hours postgame. No significant difference existed among time points for salivary testosterone and CRP. Cortisol levels significantly increased postgame compared with baseline (p < 0.05). Total mood disturbance, assessed by POMS, and daily wellness markers for energy were significantly decreased (p < 0.05), whereas daily wellness markers for soreness were significantly increased (p < 0.05) immediately after the game. Players exhibited a significant decrease in PRS up to 44 hours postgame (p < 0.05), similar to the decrease in neuromuscular function. Neuromuscular function and PRS are impaired for up to 44-68 h postgame.

Blood and affective markers of stress in Elite Airmen during a preparatory training course: A pilot study

In highly stressful environments, individuals with diverging stress-reactivity can perform differently. Identification of blood markers of stress-reactivity is of major significance to help human performance during stress. Candidate transcripts were identified between stressed and non-stressed strains of rats’ blood and brain, and overlapping significant differentially expressed genes were selected. Serum levels of human orthologues of these proteins, in lieu of blood RNA, in addition to classic stress and general clinical markers, were measured in 33 Battlefield Airmen undergoing a 52 day long preparatory training course before their course of initial entry (COIE). Blood samples and factors of affective state, negative valence “Threat” and positive valence “Challenge”, were obtained five times across different days of training which included either routine physical exercise or prolonged and intense physical and mental training. During training, levels of chloride (Cl), dehydroepiandrosterone-sulfate (DHEA-S), creatinine kinase (CK), and total carbon dioxide (TCO2) differed between airmen who subsequently graduated from their COIE and those who did not. Time dependent changes of serum TCO2 and neuropeptide Y (NPY), as well as the affective factor Challenge differed by future graduation status throughout the training. Serum levels of parvin beta (PARVB) correlated with the affective factor Threat, while those of NPY, testosterone, coactosin like F-actin binding protein 1 (COTL1) and C-reactive protein (CRP) correlated with factor Challenge during the extended, intensive periods of training, consistently. These pilot data suggest that the identified panel of blood markers can measure stress responsiveness, which has the potential to advance individualized stress-management strategies.

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Levels of novel and classical serum markers signal stress severity in men.

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Biomarker levels reflect stress reactivity of Battlefield Airmen in training.

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Affective measures correlate with serum biomarkers after extended stress.

Test and Evaluation of Heart Rate Derived Core Temperature Algorithms for Use in NCAA Division I Football Athletes

The purpose of this study was to assess the validity of utilizing heart rate to derive an estimate of core body temperature in American Football athletes. This was evaluated by combining commercially available Zephyr Bioharness devices, which includes an embedded estimated core temperature (ECT) algorithm, and an ingestible radio frequency core temperature pill during the highest heat injury risk timepoint of the season, summer training camp. Results showed a concordance of 0.643 and 78% of all data points fell within +/-1.0 °F. When the athletes were split into Upper (>/=6.0%) and Lower (<6.0%) body composition groups, there was a statistical improvement in accuracy with the Upper Body Fat% reaching 0.834 concordance and 93% of all values falling within +/-1.0 °F of the Gold Standard. Results suggest that heart rate derived core temperature assessments are a viable tool for heat stress monitoring in American football, but more work is required to improve on accuracy based on body composition.

Treating exercise-associated low testosterone and its related symptoms

The Exercise-Hypogonadal Male Condition (EHMC) has been described to occur in athletes who experience low serum testosterone and associated symptoms. While high volumes of endurance exercise can lead to reduced testosterone concentrations in men, similar changes may occur in other sports including anerobic and power sports such as American football, and weight class sports such as wrestling. A reduced testosterone concentration alone does not necessarily warrant treatment, but when it is accompanied by symptoms of hypogonadism, such as fatigue, sexual dysfunction, and/or low bone mineral density (BMD), an athlete's performance and/or health may suffer. While pharmacological treatments such as testosterone or clomiphene citrate have been shown to be effective in treating hypogonadism, these options are not available to athletes competing in sports governed by the World Anti-Doping Agency. We recommend treatment of EHMC in athletes should include nutritional intervention and modification of training. Recognizing EHMC's existence in male athletes is important to optimize their health.

The Relationship Between Handball Players and Alcohol and Smoking Habits

Recent studies have revealed that sport activity is a protective factor regarding smoking, but a risk factor for alcohol abuse. Considering these findings, it is necessary to investigate the occurrence of substance misuse. Sports that are associated with a substantial amount of physical/mental stress are very interesting from the perspective of substance misuse (e.g., handball). This research was performed to more closely study the population engaged in handball regarding the risk for alcohol and/or tobacco consumption. The sample of respondents consisted of 150 senior handball players who were members of 9 first-league handball clubs from Croatia and abroad. The respondents were grouped into sub-samples according to sex, age, experience, the number of weekly training sessions and their social environment (clubs). Alcohol consumption data were obtained using the AUDIT questionnaire. The differences between groups were tested using the Kruskal-Wallis and Mann-Whitney U tests. The study revealed that handball players engaged in alcohol misuse, and they were grouped in the harmful drinking category (AUDIT score, 16-19 for all groups). Regarding tobacco product consumption, the risk groups were women (who smoked significantly more than men, MWU test: Z = 3.30. p < 0.001), handball players with less experience (who smoked significantly more than experienced players, MWU test: Z = 3.68, p < 0.001). Borderline significance was observed for the impact made by social environments, and age was not a significant predictor of tobacco consumption. Regarding alcohol consumption, the highest hazard group were national handball players, who drank much more than foreign players did (MWU test: Z = 2.04, p = 0.04); however, sex, age, experience and training habits were not alcohol consumption predictors in handball. This study reveal that the typical behaviors regarding alcohol and tobacco consumption followed by the general population do not apply to handball players. Targeted prevention can be much more precisely established considering this research.