Ken A. van Someren

The ACE gene and human performance: 12 years on.

Some 12 years ago, a polymorphism of the angiotensin I-converting enzyme (ACE) gene became the first genetic element shown to impact substantially on human physical performance. The renin-angiotensin system (RAS) exists not just as an endocrine regulator, but also within local tissue and cells, where it serves a variety of functions. Functional genetic polymorphic variants have been identified for most components of RAS, of which the best known and studied is a polymorphism of the ACE gene. The ACE insertion/deletion (I/D) polymorphism has been associated with improvements in performance and exercise duration in a variety of populations. The I allele has been consistently demonstrated to be associated with endurance-orientated events, notably, in triathlons. Meanwhile, the D allele is associated with strength- and power-orientated performance, and has been found in significant excess among elite swimmers. Exceptions to these associations do exist, and are discussed.In theory, associations with ACE genotype may be due to functional variants in nearby loci, and/or related genetic polymorphism such as the angiotensin receptor, growth hormone and bradykinin genes. Studies of growth hormone gene variants have not shown significant associations with performance in studies involving both triathletes and military recruits. The angiotensin type-1 receptor has two functional polymorphisms that have not been shown to be associated with performance, although studies of hypoxic ascent have yielded conflicting results. ACE genotype influences bradykinin levels, and a common gene variant in the bradykinin 2 receptor exists. The high kinin activity haplotye has been associated with increased endurance performance at an Olympic level, and similar results of metabolic efficiency have been demonstrated in triathletes.Whilst the ACE genotype is associated with overall performance ability, at a single organ level, the ACE genotype and related polymorphism have significant associations. In cardiac muscle, ACE genotype has associations with left ventricular mass changes in response to stimulus, in both the health and diseased states. The D allele is associated with an exaggerated response to training, and the I allele with the lowest cardiac growth response. In light of the I-allele association with endurance performance, it seems likely that other regulatory mechanisms exist. Similarly in skeletal muscle, the D allele is associated with greater strength gains in response to training, in both healthy individuals and chronic disease states. As in overall performance, those genetic polymorphisms related to the ACE genotype, such as the bradykinin 2 gene, also influence skeletal muscle strength.Finally, the ACE genotype may influence metabolic efficiency, and elite mountaineers have demonstrated an excess of I alleles and I/I genotype frequency in comparison to controls. Interestingly, this was not seen in amateur climbers. Corroboratory evidence exists among high-altitude settlements in both South America and India, where the I allele exists in greater frequency in those who migrated from the lowlands. Unfortunately, if the ACE genotype does influence metabolic efficiency, associations with peak maximal oxygen consumption have yet to be rigorously demonstrated.The ACE genotype is an important but single factor in the determinant of sporting phenotype. Much of the mechanisms underlying this remain unexplored despite 12 years of research.

Compression garments and recovery from exercise-induced muscle damage: a meta-analysis

The purpose of the study was to determine the effects of compression garments on recovery following damaging exercise. A systematic review and meta-analysis was conducted using studies that evaluated the efficacy of compression garments on measures of delayed onset muscle soreness (DOMS), muscular strength, muscular power and creatine kinase (CK). Studies were extracted from a literature search of online databases. Data were extracted from 12 studies, where variables were measured at baseline and at 24 or 48 or 72 h postexercise. Analysis of pooled data indicated that the use of compression garments had a moderate effect in reducing the severity of DOMS (Hedges’ g=0.403, 95% CI 0.236 to 0.569, p<0.001), muscle strength (Hedges’ g=0.462, 95% CI 0.221 to 0.703, p<0.001), muscle power (Hedges’ g=0.487, 95% CI 0.267 to 0.707, p<0.001) and CK (Hedges’ g=0.439, 95% CI 0.171 to 0.706, p<0.001). These results indicate that compression garments are effective in enhancing recovery from muscle damage.

Genetic Influences in Sport and Physical Performance

The common inheritance of approximately 20 000 genes defines each of us as human. However, substantial variation exists between individual human genomes, including ‘replication’ of gene sequences (copy number variation, tandem repeats), or changes in individual base pairs (mutations if <1% frequency and single nucleotide polymorphisms if >1% frequency). A vast array of human phenotypes (e.g. muscle strength, skeletal structure, tendon elasticity, and heart and lung size) influences sports performance, each itself the result of a complex interaction between a myriad of anatomical, biochemical and physiological systems. This article discusses the role for genetic influences in influencing sporting performance and injury, offering specific exemplars where these are known. Many of these preferable genotypes are uncommon, and their combination even rarer. In theory, the chances of an individual having a perfect sporting genotype are much lower than 1 in 20 million — as the number of associated polymorphisms increase, the odds decrease correspondingly. Many recently discovered polymorphisms that may affect sports performance have been described in animal or other human based models, and have been included in this review if they may apply to athletic populations. Muscle performance is heavily influenced by basal muscle mass and its dynamic response to training. Genetic factors account for approximately 5080%of inter-individual variation in lean body mass, with impacts detected on both training-naive’ muscle mass and its growth response. Several cytokines such as interleukin-6 and -15, cilliary neurotrophic factor and insulin-like growth factor (IGF) have myoanabolic effects. Genotype-associated differences in endocrine function, necessary for normal skeletal muscle growth and function, may also be of significance, with complex interactions existing between thyroxine, growth hormone and the downstream regulators of the anabolic pathways (such as IGF-1 and IGF-2). Almost 200 polymorphisms are known to exist in the vitamin D receptor (VDR) gene. VDR genotype is associated with differences in strength in premenopausal women. VDR expression decreases with age and VDR genotype is associated with fatfree mass and strength in elderly men and women. Muscle fibre type determination is complex. Whilst initial composition is likely to be strongly influenced by genetic factors, training has significant effects on fibre shifts. Polymorphisms of the peroxisome proliferator-activated receptor a (PPARa) gene and R577x polymorphism of the ACTN3 gene are both associated with specific fibre compositions. Alterations in cardiac size have been associated with both increased performance and excess cardiovascular mortality. PPARa is a ligand-activated transcription factor that regulates genes involved in fatty acid uptake and oxidation, lipid metabolism and inflammation. Psychology plays an important role in training, competition, tolerance of pain and motivation. However, the role of genetic variation in determining psychological state and responses remains poorly understood; only recently have specific genes been implicated in motivational behaviour and maintenance of exercise. Thyroid hormone receptors exist within the brain and influence both neurogenesis and behaviour. With the current state of knowledge, the field of genetic influences on sports performance remains in its infancy, despite over a decade of research.

The reliability of electromechanical delay and torque during isometric and concentric isokinetic contractions

The purpose of this investigation was to examine the intra-subject reliability of electromechanical delay (EMD) and torque of the dominant and non-dominant elbow flexors during isometric and isokinetic muscle contractions repeated over five consecutive days. Eleven volunteers that were unfamiliar with isokinetic dynamometry participated in this study and were asked to attend the laboratory on five consecutive days. An isokinetic dynamometer was used to exercise the elbow flexors under isometric, slow (60 degrees s(-1)) and fast (210 degrees s(-1)) isokinetic conditions; surface electromyography was recorded from the belly of biceps brachii and the signal was synchronised with the dynamometer to determine EMD. Intra-subject reliability for all measures was good (CV range, 3.1-6.5%) with no discernable difference between the dominant and non-dominant arms during isometric and isokinetic conditions. In addition, there was little difference in EMD and torque variability between the dominant and non-dominant arms which may have applications for clinicians and future research design when monitoring and investigating human muscle function. These data provide researchers and clinicians with an indication of the magnitude of change that is required to elucidate the presence of a meaningful change to muscle function in the elbow flexors.

Exercise-induced muscle damage is not attenuated by β-hydroxy-β- methylbutyrate and α-ketoisocaproic acid supplementation

Nunan, D, Howatson, G, and van Someren, KA. Exercise-induced muscle damage is not attenuated by β-hydroxy-β-methylbutyrate and α-ketoisocaproic acid supplementation. J Strength Cond Res 24(2): 531-537, 2010-The purpose of this study was to examine the effects of combined oral β-hydroxy-β-methylbutyrate (HMB) and α-ketoisocaproic acid (KIC) supplementation on indices of exercise-induced muscle damage (EIMD) after an acute bout of eccentric-biased exercise. Fourteen male subjects were allocated to 2 groups: a placebo group (3 g·d−1 corn flour, N = 7) or an HMB + KIC group (3 g·d−1 HMB and 0.3 g·d−1 KIC, N = 7). Supplementation commenced 11 days before a 40-minute bout of downhill running and continued for 3 days post-exercise. Delayed-onset muscle soreness, mid-thigh girth, knee extensor range of motion, serum creatine kinase (CK) activity, and isometric and concentric torque were assessed pre-exercise and at 24, 48, and 72 hours post-exercise. Delayed-onset muscle soreness, CK activity, and isometric and concentric torque all changed over the 72-hour period (p < 0.05); however, HMB + KIC had no significant effect on any of the indices of muscle damage. Although 14 days HMB and KIC supplementation did not attenuate indices of EIMD after an acute bout of unaccustomed eccentric-biased exercise, there was a trend for a more rapid rate of recovery in isometric and isokinetic muscle function. β-hydroxy-β-methylbutyrate and KIC may therefore provide limited benefit in the recovery of muscle function after EIMD in untrained subjects or after unaccustomed exercise.

Physiological monitoring of the Olympic athlete

Abstract As the winning margin in Olympic competition is so small, there is a continuous quest for improvements in the preparation of athletes at this standard. Therefore, even the smallest physiological improvements that result from modifications in training strategy, preparation regime or ergogenic aids are potentially useful. Unfortunately, there is a lack of research data on elite competitors, which limits our interpretation of current literature to the elite sporting environment. This places extra responsibility on the physiologist to carefully consider the most appropriate physiological variables to monitor, the best protocols to assess those variables, and the accurate interpretation of the test results. In this paper, we address the key issues of ecological validity, measurement error, and interpretation for the most commonly monitored physiological variables. Where appropriate, we also indicate areas that would benefit from further research.

A mixed exercise training programme is feasible and safe and may improve quality of life and muscle strength in multiple myeloma survivors

BackgroundExercise programmes are beneficial for cancer patients however evidence is limited in patients with multiple myeloma (MM), a cancer that is characterised by osteolytic bone disease, giving rise to high levels of bone morbidity including fractures and bone pain.MethodsWe conducted a single arm phase 2 study of an exercise programme (EP) as rehabilitation for treated MM patients, to evaluate feasibility, effects on QOL and physiological parameters. Patients were given individualised programmes, comprising stretching, aerobic and resistance exercises, carried out under supervision for 3 months then at home for a further 3 months.ResultsStudy uptake was high, 60 of 75 (80%) patients approached consented to the study. Screen failures (11, due to fracture risk and disease relapse) and patient withdrawals (12) resulted in a final 37 patients enrolling on the programme. These 37 patients demonstrated high attendance rates in the supervised classes (87%), and high levels of adherence in home exercising (73%). Patients reported better QOL following the EP, with improvement in FACT-G and Fatigue scores over time from baseline (p<0.01 for both, one-way repeated measures ANOVA) to 6 months. Upper and lower limb strength also improved on the EP, from baseline to 6 months (p<0.01 for both). There were no adverse reactions.ConclusionsAn EP in MM patients is feasible and safe, with high attendance and adherence. Benefits in QOL, fatigue and muscle strength await confirmation in randomized studies, prompting urgent evaluation of the benefits of EP in the rehabilitation of MM patients.

Influence of compression garments on recovery after marathon running.

Abstract Hill, JA, Howatson, G, van Someren, KA, Walshe, I, and Pedlar, CR. Influence of compression garments on recovery after marathon running. J Strength Cond Res 28(8): 2228–2235, 2014—Strenuous physical activity can result in exercise-induced muscle damage. The purpose of this study was to investigate the efficacy of a lower limb compression garment in accelerating recovery from a marathon run. Twenty four subjects (female, n = 7; male, n = 17) completed a marathon run before being assigned to a treatment group or a sham treatment group. The treatment group wore lower limb compression tights for 72 hours after the marathon run, the sham treatment group received a single treatment of 15 minutes of sham ultrasound after the marathon run. Perceived muscle soreness, maximal voluntary isometric contraction (MVIC), and serum markers of creatine kinase (CK) and C-reactive protein (C-RP) were assessed before, immediately after, and 24, 48, and 72 hours after the marathon run. Perceived muscle soreness was significantly lower (p ⩽ 0.05) in the compression group at 24 hours after marathon when compared with the sham group. There were no significant group effects for MVIC, CK, and C-RP (p > 0.05). The use of a lower limb compression garment improved subjective perceptions of recovery; however, there was neither a significant improvement in muscular strength nor a significant attenuation in markers of exercise-induced muscle damage and inflammation.

Recovery and Adaptation From Repeated Intermittent-Sprint Exercise

PURPOSE This investigation aimed to ascertain a detailed physiological profile of recovery from intermittent-sprint exercise of athletes familiar with the exercise and to investigate if athletes receive a protective effect on markers of exercise-induced muscle damage (EIMD), inflammation, and oxidative stress after a repeated exposure to an identical bout of intermittent-sprint exercise. METHODS Eight well-trained male team-sport athletes of National League or English University Premier Division standard (mean ± SD age 23 ± 3 y, VO2max 54.8 ± 4.6 mL ·kg-1 · min-1) completed the Loughborough Intermittent Shuttle Test (LIST) on 2 occasions, separated by 14 d. Maximal isometric voluntary contraction (MIVC), countermovement jump (CMJ), creatine kinase (CK), C-reactive protein (CRP), interleukin-6 (IL-6), F2-isoprostanes, and muscle soreness (DOMS) were measured before and up to 72 h after the initial and repeated LISTs. RESULTS MIVC, CMJ, CK, IL-6, and DOMS all showed main effects for time (P < .05) after the LIST, indicating that EIMD was present. DOMS peaked at 24 h after LIST 1 (110 ± 53 mm), was attenuated after LIST 2 (56 ± 39 mm), and was the only dependent variable to demonstrate a reduction in the second bout (P = .008). All other markers indicated that EIMD did not differ between bouts. CONCLUSION Well-trained games players experienced EIMD after exposure to both exercise tests, despite being accustomed to the exercise type. This suggests that well-trained athletes receive a very limited protective effect from the first bout.

Oral health and elite sport performance

While the research base is limited, studies have consistently reported poor oral health in elite athletes since the first report from the 1968 Olympic Games. The finding is consistent both across selected samples attending dental clinics at major competitions and more representative sampling of teams and has led to calls from the International Olympic Committee for more accurate data on oral health. Poor oral health is an important issue directly as it can cause pain, negative effects on appearance and psychosocial effects on confidence and quality of life and may have long-term consequences for treatment burden. Self-reported evidence also suggests an impact on training and performance of athletes. There are many potential challenges to the oral health of athletes including nutritional, oral dehydration, exercise-induced immune suppression, lack of awareness, negative health behaviours and lack of prioritisation. However, in theory, oral diseases are preventable by simple interventions with good evidence of efficacy. The consensus statement aims to raise awareness of the issues of oral health in elite sport and recommends strategies for prevention and health promotion in addition to future research strategies.