Non-athletic Controls Research Articles

Doppler echocardiography in athletes from different sports.

BackgroundStudies have shown cardiac changes induced by intense and regular physical activity. The purpose of this study was to evaluate cardiac structures and function in soccer players, cyclists and long-distance runners, and compare them with non-athlete controls.Material/MethodsCardiac structural, systolic, and diastolic function parameters in 53 athletes and 36 non-athlete controls were evaluated by Doppler echocardiography.ResultsAthletes presented higher left atrial volume, left ventricular (LV) thickness, and LV and right ventricular (RV) diastolic diameters (LVDD and RVDD, respectively) compared to non-athletes. Left atrium and LVDD were higher in cyclists than runners, and RVDD was higher in cyclists than soccer players. LV mass index was higher in athletes, and cyclists had higher values than runners and soccer players. LV systolic function did not differ significantly between groups. The only altered index of LV diastolic function was a higher E/A ratio in cyclists compared to controls. There was no difference in LV E/E’ ratio. RV systolic function evaluated by tissue Doppler imaging was higher in cyclists and soccer players than runners. There were no conclusive differences in RV diastolic function.ConclusionsSoccer players, runners and cyclists had remodeling of left and right ventricular structures compared to controls. Cardiac remodeling was more intense in cyclists than runners and soccer players.

Patellar tendon morphology in volleyball athletes with and without patellar tendinopathy

Appropriate management of patellar tendinopathy requires distinguishing between inflammatory and degenerative conditions, often difficult because tendon thickening can be a normal or pathological adaptation, and micromorphology is not observable on clinical imaging. The purpose of this study was to quantitatively examine patellar tendon micro- and macromorphology in volleyball athletes and relate those findings to reported symptoms. Longitudinal ultrasound images of proximal and distal patellar tendons were acquired from 84 male elite volleyball athletes (44 symptomatic, 40 asymptomatic) and 10 asymptomatic nonathlete controls. Micromorphology was determined using two-dimensional Fast Fourier Transform analysis providing a discriminating peak spatial frequency parameter (PSF). Macromorphology (patellar tendon thickness) was measured using Image J software. All athletes regardless of symptoms had thicker proximal tendons compared to nonathletes, suggesting a normal adaptation to training loads. However, symptomatic athletes demonstrated lower PSF than asymptomatic athletes and nonathletes at the proximal tendon, suggesting greater collagen disorganization, and tendon degeneration rather than inflammation. Only symptomatic athletes had thicker distal tendons than nonathletes, but there was no difference in PSF distally. Diagnostic ultrasound enhances the understanding of the micromorphology of patellar tendons, supporting the rationale for management that remodels the degenerated tendon instead of treating inflammation.

Effects of a Flavonoid-Rich Juice on Inflammation, Oxidative Stress, and Immunity in Elite Swimmers: A Metabolomics-Based Approach

The effects of a flavonoid-rich fresh fruit and vegetable juice (JUICE) on chronic resting and postexercise inflammation, oxidative stress, immune function, and metabolic profiles (metabolomics analysis, gas-chromatography mass-spectrometry platform) in elite sprint and middle-distance swimmers were studied. In a randomized, crossover design with a 3-wk washout period, swimmers (n = 9) completed 10-d training with or without 16 fl oz of JUICE (230 mg flavonoids) ingested pre- and postworkout. Blood samples were taken presupplementation, post-10-d supplementation, and immediately postexercise, with data analyzed using a 2 × 3 repeated-measures ANOVA. Prestudy blood samples were also acquired from nonathletic controls (n = 7, age- and weight-matched) and revealed higher levels of oxidative stress in the swimmers, no differences in inflammation or immune function, and a distinct separation in global metabolic scores (R2Y [cum] = .971). Swim workouts consisted of high-intensity intervals (1:1, 1:2 swim-to-rest ratio) and induced little inflammation, oxidative stress, or immune changes. A distinct separation in global metabolic scores was found pre- to postexercise (R2Y [cum] = .976), with shifts detected in a small number of metabolites related to substrate utilization. No effect of 10-d JUICE was found on chronic resting levels or postexercise inflammation, oxidative stress, immune function, and shifts in metabolites. In conclusion, sprint and middle-distance swimmers had a slight chronic elevation in oxidative stress compared with nonathletic controls, experienced a low magnitude of postworkout perturbations in the biomarkers included in this study, and received no apparent benefit other than added nutrient intake from ingesting JUICE pre- and postworkout for 10 days.

Sport-specific association between exercise loading and the density, geometry, and microstructure of weight-bearing bone in young adult men

SummaryIn this population-based study of 24-year-old men, we have investigated the association between sport-specific exercise loading and different bone parameters. We reveal that the association between exercise loading and bone parameters is sport-specific, indicating that nonspecific resistance exercise does not impact bone density, geometry, or microstructure in young men.IntroductionIn this cross-sectional study, the association between nonspecific resistive exercise and areal and volumetric bone density, bone geometry, or bone microstructure was investigated in young adult men.MethodsA total of 184 male athletes, 24.0 ± 0.6 years of age (mean ± SD), representing nonspecific resistive exercise and soccer (proportion of recreational athletes, 93.4 and 7.7 %, respectively), and 177 nonathletic age-matched controls were measured with dual-energy X-ray absorptiometry. Radius and tibia were measured by peripheral quantitative computed tomography (pQCT) at the diaphysis and by three-dimensional pQCT at the metaphysis.ResultsMen in the nonspecific resistive exercise group had higher grip strength(9.1 % or 0.4 SD) and higher lean mass(5.6 % or 0.5 SD) than those in the nonathletic group(p < 0.01 and p < 0.001, respectively). However, men who participated in nonspecific resistive exercise did not have higher bone density or a more favorable bone microstructure or geometry than their nonathletic referents. In contrast, men playing soccer had higher areal bone mineral density (aBMD) at the femoral neck (19.5 % or 1.2 SD) and lumbar spine (12.6 % or 1.0 SD), as well as larger cortical cross-sectional area (16.4 % or 1.1 SD) and higher trabecular bone volume fraction (14.5 % or 0.9 SD), as a result of increased trabecular number (8.7 % or 0.6 SD) and thickness (5.7 % or 0.4 SD) at the tibia than men in the nonathletic group(p < 0.001).ConclusionsWeight-bearing exercise with impacts from varying directions (playing soccer) is associated with aBMD and volumetric BMD, cortical bone geometry, as well as trabecular microstructure of weight-bearing bone. Nonspecific recreational resistance exercise does not appear to be a strong determinant of bone density, geometry, or microstructure in young adult men.

Changes in natural killer cell subpopulations over a winter training season in elite swimmers

Immune changes and increased susceptibility to infection are often reported in elite athletes. Infectious episodes can often impair training and performance with consequences for health and sporting success. This study monitored the occurrence of episodes of upper respiratory symptoms (URS) and the variation in circulating NK cells, CD56(bright) and CD56(dim) NK cells subpopulations, over a winter swimming season. Nineteen national elite swimmers and 11 non-athlete controls participated in this study. URS episodes were monitored using daily log books. Blood samples were taken at rest at four time points during the season: before the start of the season (t1--middle September), after 7 weeks of an initial period of gradually increasing training load (t2--early November), after 6 weeks of an intense training cycle (t3--late February) and 48 h after the main competition (t4--early April) and from the controls at three similar time points (t1--early November; t2--late February; t3--early April). In the swimmers, the occurrence of URS clustered around the periods of elevated training load (67 %). No URS were reported at equivalent time points in the non-athletes. Athletes showed a decrease in the percentage (t2 = 21 %; t3 = 27 %; t4 = 17 %) and absolute counts of circulating NK cells (t2 = 35 %; t3 = 22 %; t4 = 22 %), coinciding with the periods of increased training load, never recovering to the initial values observed at the start of the season. The reduction in the CD56(dim) and an increase in the CD56(bright) NK cell subpopulations were significant at t2 and t3 (p < 0.05). Concomitant with the fall in values of NK cells, in athletes that shown more than three URS episodes, a moderate correlation (r = 0.493; p = 0.036) was found between CD56(bright)/CD56(dim) ratio and the number of URS episodes after the more demanding training phase (t3). At t3, a lower value of CD56 cell counts was found in the group who reported three or more URS episodes (t = 2.239; p = 0.032). A progressive significant decrease in the expression of CD119, the receptor for IFN-γ, on the CD56(dim) cells was found over the season and an elevation in Granzyme B expression was coincident with the more demanding training phases. Periods of highly demanding training seem to have a negative impact on innate immunity mediated by NK cell subsets, which could partially explain the higher frequency of URS observed during these training phases.

The Prevalence of Low Back Pain Among Former Elite Cross-Country Skiers, Rowers, Orienteerers, and Nonathletes

Background: Some cross-sectional studies have suggested that the prevalence of low back pain (LBP) may be high among endurance athletes with repetitive back loading, but there are no large, prospective cohort studies addressing this issue. Purpose: To compare the prevalence of symptoms of low back pain (LBP) among former endurance athletes with different loading characteristics on the lumbar region: cross-country skiing (flexion loading), rowing (extension loading), and orienteering (no specific loading), as well as a nonathletic control group. Study design: Cohort study; level of evidence, 2. Methods: Self-reported questionnaire on LBP adapted for sports based on standardized Nordic questionnaires for musculoskeletal symptoms. Responders were 173 rowers, 209 orienteerers, 242 cross-country skiers, and 116 control subjects (88% of the original cohort). Results: There were no group differences between the athletic groups and the control group with regard to the 2 main outcomes: reported LBP the previous 12 months (P = .66) and frequent LBP the past year (>30 days with LBP) (P = .14). More rowers than orienteerers reported frequent LBP the past year (adjusted OR = 2.32; CI, 1.02-5.28). Occupational changes due to LBP were reported more often by rowers (13%) than skiers (7%) and orienteerers (3%) (P = .002). More rowers and skiers reported having received outpatient medical assistance than orienteerers or controls. A training volume >550 h/y was a risk factor for reporting LBP during the previous 12 months compared with a training volume <200 h/y (adjusted OR = 2.51; CI, 1.26-5.02). A previous episode with LBP was associated with LBP later in life (adjusted OR = 3.02; CI, 2.22-4.10). Conclusion: Low back pain was not more common among former endurance athletes with specific back loading compared with non-athletes. The results indicate that years of prolonged and repetitive flexion or extension loading in endurance sports does not lead to more LBP. However, a large training volume in the past year and previous episodes with LBP are risk factors for LBP. Comparing the sports of rowing, cross-country skiing, and orienteering, it appears that whereas orienteering is protective, rowing can provoke LBP.

The ACTN3 R577X Polymorphism across Three Groups of Elite Male European Athletes

The ACTN3 R577X polymorphism (rs1815739) is a strong candidate to influence elite athletic performance. Yet, controversy exists in the literature owing to between-studies differences in the ethnic background and sample size of the cohorts, the latter being usually low, which makes comparisons difficult. In this case:control genetic study we determined the association between elite athletic status and the ACTN3 R577X polymorphism within three cohorts of European Caucasian men, i.e. Spanish, Polish and Russian [633 cases (278 elite endurance and 355 power athletes), and 808 non-athletic controls]. The odds ratio (OR) of a power athlete harbouring the XX versus the RR genotype compared with sedentary controls was 0.54 [95% confidence interval (CI): 0.34–0.48; P = 0.006]. We also observed that the OR of an endurance athlete having the XX versus the RR genotype compared with power athletes was 1.88 (95%CI: 1.07–3.31; P = 0.028). In endurance athletes, the OR of a “world-class” competitor having the XX genotype versus the RR+RX genotype was 3.74 (95%CI: 1.08–12.94; P = 0.038) compared with those of a lower (“national”) competition level. No association (P>0.1) was noted between the ACTN3 R577X polymorphism and competition level (world-class versus national-level) in power athletes. Our data provide comprehensive support for the influence of the ACTN3 R577X polymorphism on elite athletic performance.

Noncompaction cardiomyopathy, a frequently overlooked entity (…but beware of over diagnosis!)

Noncompaction cardiomyopathy, a frequently overlooked entity (…but beware of over diagnosis!)

Assessment of electrocardiography, echocardiography, and heart rate variability in dynamic and static type athletes

Background:Over the last two decades, morphological cardiac changes induced by athletic conditioning have been of great interest. Therefore, several studies have been orchestrated to delineate electrocardiography (ECG), echocardiography, and heart rate variability (HRV) findings in athletes.Purpose:To assess the ECG, echocardiography, and HRV in a group of dynamic and static type athletes.Methods:Fifty professional athletes (20 static and 30 dynamic exercise athletes) and 50 healthy nonathletes (control group) were recruited. Standard 12-lead ECG and transthoracic echocardiography was performed on all athletes and the control group. Through echocardiography, variables including left ventricular (LV) end-diastolic/systolic diameter, LV mass, and left atrial volume index were measured. In addition, both the athletes and the control group underwent ECG Holter monitoring for 15 minutes and several parameters related to HRV (time and frequency domain) were recorded.Results:The most common ECG abnormalities among the athletes were sinus bradycardia and incomplete right bundle branch block. LV end-diastolic diameter and left atrial volume index were significantly greater in the dynamic athletes (P < 0.001). LV end-systolic diameter was significantly lower in the static group (P < 0.001). LV mass of the dynamic and static athletes was significantly greater than that of the controls (P < 0.001). Among the ECG Holter monitoring findings, the dynamic athletes had lower systolic blood pressure than the controls (P = 0.01). Heart rate was lowest in the control group (P < 0.001).Conclusion:The most common ECG abnormalities among adolescent Iranian athletes were sinus bradycardia and incomplete right bundle branch block. Static exercise seemed to reduce LV end-systolic diameter, while dynamic exercise resulted in increased LV end-diastolic diameter and left atrial volume index. Additionally, Iranian athletes showed no differences in HRV parameters, excluding heart rate and systolic blood pressure, compared with the nonathletes.

The rs12594956 polymorphism in the NRF-2 gene is associated with top-level Spanish athlete's performance status

ObjectivesTo determine the association between the nuclear respiratory factor 2 (NRF-2) polymorphisms and elite athletic performance. DesignWe compared the genotype and allele frequencies of the NRF-2 A/C (rs12594956), NRF-2 A/G (rs7181866), and NRF-2 C/T (rs8031031) polymorphisms between world-class endurance athletes (n=89), elite power-oriented athletes (n=38), and non-athletic controls (n=110) of the same Caucasian (Spanish) origin. MethodsGenomic DNA was extracted from peripheral EDTA-treated, anti-coagulated blood using a standard protocol. Genotyping was performed using polymerase chain reaction (PCR). ResultsThe frequency of the AA genotype of the NRF-2 A/C (rs12594956) polymorphism was significantly higher in endurance athletes compared with power athletes (P<0.01) and controls (P<0.01) (48% vs. 13% and 21%, respectively). The likelihood of having the AA (rs12594956) genotype was higher in elite endurance athletes compared with controls [odds ratio (OR): 3.536, 95% confidence interval (CI): 1.903–6.571] and elite power athletes (OR: 6.170, 95%CI: 2.206–17.253). ConclusionsOur results suggest that the NRF-2 A/C polymorphism might belong to a growing group of polymorphisms associated with endurance performance at the elite level. However, it is important to replicate these findings in other groups of elite athletes using larger sample sizes.

Are Under- and Overweight Female Elite Athletes Thin and Fat? A Controlled Study

The study's purpose was to relate body mass index (BMI) to body fat percentage as measured by dual-energy x-ray absorptiometry in female elite athletes from different sports and nonathletic controls and to investigate what characterizes the athletes with unhealthy low and high body fat values. This study was conducted in three phases: 1) screening with a detailed questionnaire, 2) body composition measurement (dual-energy x-ray absorptiometry), and 3) clinical interview. All female elite athletes representing national teams at the junior or senior level age 13-39 yr (n = 938) and an age group-matched randomly selected population-based control group (n = 900) were invited to participate. A stratified random sample was invited to participate in parts 2 and 3. A total of 186 athletes (62%) and 145 controls (48%) participated in all three phases. Of those athletes with normal BMI values (18.5-24.9 kg·m⁻²) (n = 150), 2.0% were classified with low body fat levels (<12%), and 6.7% were classified with obese body fat levels (≥ 33%). The median value for the entire group was 24.3% body fat. For the controls with normal BMI values (n = 96), none was classified with low body fat levels, and 50% were classified with obese body fat levels (median = 33.1%). The correlation between BMI and body fat percentage was 0.671 (P < 0.01) (SEE = 5.3%) for the athletes and 0.813 (P < 0.01) (SEE = 4.1%) for the controls. Both under- and overfat athletes self-reported menstrual dysfunction, stress fractures, history of weight fluctuation, and use of pathogenic weight control methods and were diagnosed with clinical eating disorders and/or low bone density. Our data show that BMI is not a valid measure for assessing or monitoring body composition in female elite athletes, and it should be used carefully in female nonathletes.

The C Allele in NOS3 -786 T/C Polymorphism is Associated with Elite Soccer Player's Status

The NOS3-786 T/C polymorphism (rs2070744) is a candidate to explain individual variations in sports related phenotypes. We determined the genotype and allele frequency of NOS3-786 T/C in a group of 60 male professional elite soccer players. Their results were compared with those of 100 world-class endurance athletes, 53 elite power athletes, and 100 sedentary, healthy men (controls) of the same Caucasian (Spanish) origin. There were significant differences in genotype frequencies between soccer players, controls, endurance and power elite athletes (all P ≤ 0.02). These results were confirmed when we analysed allelic frequencies (all P<0.01). The likelihood of having the C allele was higher in soccer players compared with (i) controls [odds ratio (OR), 2.165, 95% confidence interval (CI): 1.362-3.441], (ii) endurance athletes (OR: 1.879, 95%CI: 1.184-2.984), and (iii) power athletes (OR: 4.032, 95%CI: 2.307-7.047). In conclusion, the -786C allele is associated with the status of being an elite soccer player, compared with non-athletic controls and also with elite endurance and power athletes. More research is needed in other groups of elite soccer players in order to replicate the results of the present study.

Knee osteoarthritis among ex-professional male soccer players compared to non-athletes

Introduction: The advantages of physical activities have recently been recommended in preventing such chronic diseases as osteoarthritis. However, the risks that severe physical activity may have on musculoskeletal system of athletes are still unknown. The purpose of this study was to compare the radiographic grading scales of osteoarthritis, knee pain, existing symptoms, physical functions in activities of daily living, sports and recreation, and the quality of life of ex - elite soccer players with the same factors in non-athlete controls. Materials and Methods: 15 ex-elite male soccer athletes and 15 non-athletes were purposefully selected in this study. The clinical and radiological methods (Kellgren-Lawrence) along with an internationally-known and translated questionnaire called “Knee Injury and Osteoarthritis Outcome Score” (KOOS) were used to diagnose the disease. Statistical analysis of data was performed via independent t test at significance level of P ≤ 0.05. Results: Mean scores of radiographic grading scales for osteoarthritis of the knee (P = 0.001) was significantly higher in ex-professional athletes than in non-athlete controls. There was, however, a significant lower mean scores of knee pain (P = 0.002), symptoms (P < 0.001), physical function in daily activities (P = 0.001), sport, recreation (P < 0.001) and quality of life (P < 0.001) in athletes as compared to non - athletes. Conclusion: Having a professional soccer-playing career can result in high risk of knee osteoarthritis in former elite athletes. Keywords: Knee osteoarthritis, Soccer, Ex-elite retiree

Smooth Pursuit Eye Movement Adaptation in High Level Gymnasts

This study investigated long-term adaptations of smooth pursuit eye movement characteristics in high-level gymnasts and compared these responses to those of nonathletes. Gymnasts were selected because of their exceptional ability to spatially orient during fast, multiaxial whole body rotations. Participants were tested with standardized and supra-maximal sinusoidal smooth pursuit measurements. The results showed significantly higher gain values in top-level gymnasts, followed by young federal team gymnasts, followed by the nonathlete control group. By testing participants over the course of three years and also after periods of abstinence from training, changes to patterns of smooth pursuit over time are revealed. These results have interesting implications for understanding the characteristics of eye-movements in expert populations as well as understanding the general principles that underlie oculomotor adaptation.

Sleep duration and quality in elite athletes measured using wristwatch actigraphy

Sleep is known to be an important component of recovery from training, yet little is known about the quality and quantity of sleep achieved by elite athletes. The aim of the present study was to quantify sleep in elite athletes using wristwatch actigraphy. Individual nights of sleep from a cohort of Olympic athletes (n = 47) from various sports were analysed and compared to non-athletic controls (n = 20). There were significant differences between athletes and controls in all measures apart from ‘time asleep’ (p = 0.27), suggesting poorer characteristics of sleep in the athlete group. There was a significant effect of gender on ‘time awake’ (mean difference: 12 minutes higher in males; 95% likely range: 3 to 21 minutes) and ‘sleep efficiency’ (mean difference: 2.4 lower in males; 95% likely range: 0.1 to 4.8). Athletes showed poorer markers of sleep quality than an age and sex matched non-athletic control group (Sleep efficiency: 80.6 ± 6.4% and 88.7 ± 3.6%, respectively. Fragmentation Index: 36.0 ± 12.4 and 29.8 ± 9.0, respectively) but remained within the range for healthy sleep. This descriptive study provides novel data for the purpose of characterising sleep in elite athletes.

Distribution of Bone Mineral Density at Osteochondral Donor Sites in the Patellofemoral Joint Among Baseball Players and Controls

Background: To theoretically minimize complications of osteochondral graft harvest from the knee, grafts should be obtained from the site of lowest stress distribution across the joint. Hypothesis: Long-term stress distribution over the patellofemoral (PF) joint surface is not equal in athletes. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Measurement of subchondral bone density can determine long-term resultant stress acting on an articular surface in living joints. Our analysis was performed using computed tomography (CT) image data obtained from bilateral knees of 10 college baseball fielders (fielder group) and 10 college baseball pitchers (pitcher group) and 2 control groups, including 10 college soccer players (soccer group) and 10 nonathletes (nonathlete group). The distribution pattern of subchondral bone density throughout the articular surface of the PF joint was assessed using the CT osteoabsorptiometry method. The quantitative analysis focused on the location of the low-density area at the articular surface to assess potential osteochondral donor sites. Results: All participants in the pitcher and fielder groups demonstrated a low-density area widely distributed in the proximal part of the lateral trochlea. On the other hand, a high-density area was located in the distal part of the lateral notch, of the medial notch, and of the medial trochlea. No apparent differences in the distribution pattern were found between the baseball groups and the control groups. Conclusion: Our analysis, based on CT osteoabsorptiometry, indicates that the proximal lateral trochlea of the distal femur has the highest percentage area of low bone density at the PF joint level in donor knees of baseball players, soccer players, and nonathlete controls. Clinical Relevance: From a biomechanical viewpoint, the proximal lateral trochlea is the optimal site for harvesting osteochondral grafts in performing mosaicplasty for baseball players. This selection for the donor site may minimize postoperative PF joint symptoms.

Isokinetic analysis of ankle and ground reaction forces in runners and triathletes

OBJECTIVE:To analyze and compare the vertical component of ground reaction forces and isokinetic muscle parameters for plantar flexion and dorsiflexion of the ankle between long-distance runners, triathletes, and non-athletes.METHODS:Seventy-five males with a mean age of 30.26 (±6.5) years were divided into three groups: a triathlete group (n = 26), a long-distance runner group (n = 23), and a non-athlete control group. The kinetic parameters were measured during running using a force platform, and the isokinetic parameters were measured using an isokinetic dynamometer.RESULTS:The non-athlete control group and the triathlete group exhibited smaller vertical forces, a greater ground contact time, and a greater application of force during maximum vertical acceleration than the long-distance runner group. The total work (180°/s) was greater in eccentric dorsiflexion and concentric plantar flexion for the non-athlete control group and the triathlete group than the long-distance runner group. The peak torque (60°/s) was greater in eccentric plantar flexion and concentric dorsiflexion for the control group than the athlete groups.CONCLUSIONS:The athlete groups exhibited less muscle strength and resistance than the control group, and the triathletes exhibited less impact and better endurance performance than the runners.

Left ventricular remodelling and the athlete's heart: time to revisit the Morganroth hypothesis

A widely held belief in sport cardiology is that the pattern of left ventricular (LV) remodelling associated with athletic training depends on the type of physical conditioning performed. This is based on the 1975 echocardiographic study by Morganroth et al. who found that male collegiate endurance trained (runners and swimmers) athletes had increased LV diastolic cavity size and mass with a normal wall thickness (eccentric hypertrophy) compared to age- and sex-matched non-athletic control subjects (Morganroth et al. 1975). In contrast, resistance trained athletes (wrestlers and shot putters) had increased LV wall thickness and mass with normal diastolic cavity size (concentric hypertrophy) compared to controls (Morganroth et al. 1975). The stimulus for physiological eccentric hypertrophy was attributed to the large LV volume loads (diastolic wall stress) present during endurance exercise while the stimulus for concentric hypertrophy was the result of intermittent increases in arterial pressure loading (systolic wall stress) associated with performing a Valsalva manoeuvre during lifting (Morganroth et al. 1975; Morganroth & Maron, 1977). Although evidence supports the acceptance of the ‘Morganroth hypothesis’ for endurance training, uncertainty remains if LV remodelling is an obligatory adaptation with resistance training (Haykowsky et al. 2002; Naylor et al. 2008). In a recent issue of The Journal of Physiology, Spence et al. (2011) report new data that challenge, at least for resistance training, the Morganroth hypothesis. The authors examined the effects of 6 months of endurance training (3 hours per week of walking/jogging/running, n = 10) or resistance training (3 hours per week of Olympic weightlifting and supplemental strength exercises, n = 13) followed by 6 weeks of detraining on LV morphology and function, aerobic fitness, muscle strength and body composition in younger males (mean age: 27 years). Cardiac magnetic resonance imaging (MRI) and speckle tracing echocardiography were used to assess LV morphology and function. The paper provides novel information because it is the first to directly compare the two forms of exercise using MRI, which is a much more accurate assessment of cardiac morphology than previously utilized methods (Bellenger, et al. 2000) and because it adopted a within subjects longitudinal approach, which is less affected by the limitations of scaling than previous athletic comparisons. Spence et al. reported that total maximal strength and lean mass were significantly higher after resistance training and detraining compared to baseline with no change in LV morphology and function, or aerobic fitness. In contrast, cardiac MRI derived LV mass and aerobic fitness increased significantly after endurance training and returned towards baseline after detraining. Endurance training also significantly increased LV septal wall thickness and end-diastolic volume (P = 0.05) while posterior wall thickness decreased significantly after detraining. Finally, total lean mass and strength were higher after endurance training with the former returning to baseline after detraining. The LV remodelling pattern observed by Spence et al. after 6 months of endurance training is consistent with that expected based on the Morganroth hypothesis. However, their finding that resistance training did not significantly change LV posterior or interventricular septal wall thickness or mass contradicts the expected effect for this type of exercise based on Morganroth's hypothesis. A reason for this finding is that resistance training may not acutely increase in LV systolic wall stress. Indeed, our research group previously reported that (sub)maximal leg-press exercise performed with a 2–3 s Valsalva manoeuvre was not associated with an alteration in LV end-systolic wall stress in younger healthy males (mean age: 27 years) (Haykowsky et al. 2001). This observation combined with the new cardiac MRI findings by Spence et al. suggests that the four-decade old Morganroth hypothesis with respect to resistance training mediated-LV remodelling needs revisiting.

MtDNA Haplogroups and Elite Korean Athlete Status

Mitochondrial DNA (mtDNA) variation has recently been suggested to have an association with athletic performance or physical endurance. Since mtDNA is haploid and lacks recombination, specific mutations in the mtDNA genome associated with human exercise tolerance or intolerance arise and remain in particular genetic backgrounds referred to as haplogroups. To assess the possible contribution of mtDNA haplogroup-specific variants to differences in elite athletic performance, we performed a population-based study of 152 Korean elite athletes [77 sprint/power athletes (SPA) and 75 endurance/middle-power athletes (EMA)] and 265 non-athletic controls (CON). The overall haplogroup distribution of EMA differed significantly from CON (p<0.01), but that of SPA did not. The EMA have an excess of haplogroups M* (OR 4.38, 95% CI 1.63-11.79, p=0.003) and N9 (OR 2.32, 95% CI 0.92-5.81, p=0.042), but a dearth of haplogroup B (OR 0.26, 95% CI 0.09-0.75, p=0.003) compared with the CON. Thus, our data imply that specific mtDNA lineages may provide a significant effect on elite Korean endurance status, although functional studies with larger sample sizes are necessary to further substantiate these findings.

Skeletal Mass in Adolescent Male Athletes and Nonathletes: Relationships with High-Impact Sports

Dias Quiterio, AL, Canero, EA, Baptista, FM, and Sardinha, LB. Skeletal mass in adolescent male athletes and nonathletes: relationships with high-impact sports. J Strength Cond Res 25(12): 3439-3447, 2011-This study examined the relationships between the practice of different categories of sports (high-impact vs. nonimpact) and bone status in adolescent male athletes and investigated differences from an age-matched control group. A total of 54 adolescent male athletes and 26 adolescent nonathletes were evaluated. Bone mineral density, bone mineral content (BMC), and bone area at the whole-body, limbs, and lumbar spine were determined by dual-energy x-ray absorptiometry, along with total and regional fat-free mass and body fat. The high-impact group included 34 athletes: 9 gymnasts, 18 basketball players, and 7 handball players (age: 15.7 ± 1.6 years; weight: 72.0 ± 15.0 kg; height: 178.5 ± 12.5 cm). The nonimpact group consisted of 20 swimmers (age: 16.4 ± 2.5 years; weight: 66.9 ± 10.4 kg; height: 173.7 ± 10.9 cm). The nonathletic control group included 26 male adolescents (age: 15.9 ± 2.8 years; weight: 64.7 ± 16.3 kg; height: 168.6 ± 15.1 cm). No differences were observed between the nonimpact and the control group in all bone variables, before and after adjustments for maturation level, body weight, and height (p > 0.05). After adjustments for these variables, the high-impact group displayed greater bone mass in most of the measured sites when compared to the other 2 groups (p < 0.001). Subjects in the nonimpact group showed lower values of BMC, particularly in the lower limbs, than both the high-impact and the nonathletic control groups (p < 0.05) after adjustments for maturation, high, and fat-free mass. This study reinforces the positive associations between high-impact physical activities and skeletal health in adolescent boys.