Improving team-sport player's physical performance with altitude training: from beliefs to scientific evidence

Do environmental temperatures and altitudes affect physical outputs of elite football athletes in match conditions? A systematic review of the 'real world' studies

Players involved in the various football codes compete throughout the calendar year around the world. Therefore, environmental stressors such as temperature and altitude should be considered in preparation for, and during, matches. We aimed to systematically review the observational and quasi-experimental studies that have been specifically designed to quantify the effects of temperature (hot or cold) high altitude on in-match physical performance indicators. A search of electronic databases (Web of Science, Scopus, SPORTDiscus, PubMed/MEDLINE) was conducted, with 19,424 papers identified as relevant. Following sifting in relation to the eligibility criteria, 12 papers were deemed directly relevant. The reviewed studies scored 6-9 (on a 0-9 scale) for quality assessment using a previously used scale. The major outcome variables relevant to the current review were total distance (m), high-speed running (m) and high-speed runs (count) measured during matches. Standardized effect sizes (ES) were heterogeneous across studies for total distance (ES: -0.96 to -0.14) and high-speed running (ES: -0.69 to 0.12) for >1000 m vs sea-level, time spent at the given altitude being a putative factor for this heterogeneity. Heat had mainly detrimental effects on performance, but ES were, again, heterogeneous across studies (ES: -1.25 to 0.26), dependent on temperature. Given the small number of studies that involved mostly male athletes, and large heterogeneity across studies, more research needs be conducted on physical performance in these environmental conditions, with attention paid to standardizing outcomes and broadening the approaches of studies to guide future decision-making in professional sporting environments.

Altitude, Exercise, and Skeletal Muscle Angio-Adaptive Responses to Hypoxia: A Complex Story

Hypoxia, defined as a reduced oxygen availability, can be observed in many tissues in response to various physiological and pathological conditions. As a hallmark of the altitude environment, ambient hypoxia results from a drop in the oxygen pressure in the atmosphere with elevation. A hypoxic stress can also occur at the cellular level when the oxygen supply through the local microcirculation cannot match the cells’ metabolic needs. This has been suggested in contracting skeletal myofibers during physical exercise. Regardless of its origin, ambient or exercise-induced, muscle hypoxia triggers complex angio-adaptive responses in the skeletal muscle tissue. These can result in the expression of a plethora of angio-adaptive molecules, ultimately leading to the growth, stabilization, or regression of muscle capillaries. This remarkable plasticity of the capillary network is referred to as angio-adaptation. It can alter the capillary-to-myofiber interface, which represent an important determinant of skeletal muscle function. These angio-adaptive molecules can also be released in the circulation as myokines to act on distant tissues. This review addresses the respective and combined potency of ambient hypoxia and exercise to generate a cellular hypoxic stress in skeletal muscle. The major skeletal muscle angio-adaptive responses to hypoxia so far described in this context will be discussed, including existing controversies in the field. Finally, this review will highlight the molecular complexity of the skeletal muscle angio-adaptive response to hypoxia and identify current gaps of knowledges in this field of exercise and environmental physiology.

Proposal for a Clinical Analysis of Patellar Tendon Pathologies: In Search of Efficient Therapeutic Indications

Development and advances in our understanding of basic sciences such as anatomy, biochemistry, histology, and biomechanics have led to a better knowledge of tendon injuries. Likewise, technological advances in available therapies have conditioned the rise of new therapeutic techniques, turning both diagnosis and therapeutic indications into the foundation of treatment for patellar tendon disorders. Furthermore, we often find no correlation between patellar tendon function and structure, as studied and diagnosed from images taken and referred symptoms. This statement proposes an analytic procedure that ensures a specific therapeutic goal instead of applying a specific drug or therapeutic technique, with the aim of establishing parameters that define the kind of tendinopathy clinicians see, taking into account all conditioning factors that may affect a patellar tendinopathy. These include etiological factors, systemic illnesses affecting tendons, local mechanical causes and clinical presentation, range of clinical presentations, symptom persistence, and pain location, as well as those factors described by echography, with or without the presence of neoangiogenesis and location of the pathology, and magnetic resonance imaging. Diagnosing patellar tendinopathies requires deployment of a complex and thorough assessment process for each individual case and should include all variables that basic sciences have provided. Once a diagnosis has been made, a therapeutic strategy that includes all existing variables should be established. The more precise a diagnosis is, the more selective the treatment options become.

Biochemical and functional modifications in biathlon athletes at medium altitude training / Modificările biochimice și funcționale ale atleților biatloniști după antrenament la altitudine medie

Objective: The aim of our research was to identify physiological and biochemical changes induced by training at medium altitude.

Methods: Ten biathlon athletes underwent 28-day training camp at medium altitude in order to improve their aerobic effort, following the living high-base train high-interval train low (Hi-Hi-Lo) protocol. There were investigated three categories of functional and biochemical parameters, targeting the hematological changes (RBC, HCT, HGB), the oxidative (lipoperoxid, free malondialdehyde and total malondialdehyde) and antioxidative balance (the hydrogen donor capacity, ceruloplasmin and uric acid) and the capacity of effort (the maximum aerobic power, the cardiovascular economy in effort, the maximum O2 consumption).

Results: All the biochemical and functional evaluated parameters showed significant increases between the pre-training testing and post-training testing (5.13 ± 0.11 vs. 6.50 ± 0.09, p < 0.0001 for RBC; 44.80 ± 1.22 vs. 51.31 ± 2.31, p < 0.0001 for HCT; 15.06 ± 0.33 vs. 17.14 ± 0.25, p < 0.0001 for HGB; 1.32 ± 0.04 vs.1.62 ± 0.01, p < 0.0001 for LPx; 1.61 ± 0.01 vs. 1.73 ± 0.01, p < 0.0001 for free MDA; 2.98 ± 0.08 vs. 3.37 ± 0.03, p < 0.0001 for total MDA; 45.92 ± 0.13 vs. 57.98 ± 0.12, p < 0.0001 for HD; 25.95 ± 0.13 vs. 31.04 ± 0.06, p < 0.0001 for Crp; 3.47 ± 0.03 vs.7.69 ± 0.02, p < 0.0001 for UA; 63.91 ± 1.00 vs. 81.53 ± 1.97, p < 0.0001 for MAP; 33.13 ± 0.57 vs. 57.41 ± 0.63, p < 0.0001 for CVEE; 4190 ± 50.45 vs. 5945 ± 46.48, p < 0.0001 for VO2max).

Conclusions: Aerobic effort capacity of biathlon athletes has increased in the post-training period, using Hi-Hi-Lo protocol.

Platelet concentration in platelet-rich plasma affects tenocyte behavior in vitro

Since tendon injuries and tendinopathy are a growing problem, sometimes requiring surgery, new strategies that improve conservative therapies are needed. Platelet-rich plasma (PRP) seems to be a good candidate by virtue of its high content of growth factors, most of which are involved in tendon healing. This study aimed to evaluate if different concentrations of platelets in PRP have different effects on the biological features of normal human tenocytes that are usually required during tendon healing. The different platelet concentrations tested (up to 5 × 10(6) plt/µL) stimulated differently tenocytes behavior; intermediate concentrations (0.5 × 10(6), 1 × 10(6) plt/µL) strongly induced all tested processes (proliferation, migration, collagen, and MMPs production) if compared to untreated cells; on the contrary, the highest concentration had inhibitory effects on proliferation and strongly reduced migration abilities and overall collagen production but, at the same time, induced increasing MMP production, which could be counterproductive because excessive proteolysis could impair tendon mechanical stability. Thus, these in vitro data strongly suggest the need for a compromise between extremely high and low platelet concentrations to obtain an optimal global effect when inducing in vivo tendon healing.