Boris Gojanovic

2016 Consensus statement on return to sport from the First World Congress in Sports Physical Therapy, Bern

Deciding when to return to sport after injury is complex and multifactorial—an exercise in risk management. Return to sport decisions are made every day by clinicians, athletes and coaches, ideally in a collaborative way. The purpose of this consensus statement was to present and synthesise current evidence to make recommendations for return to sport decision-making, clinical practice and future research directions related to returning athletes to sport. A half day meeting was held in Bern, Switzerland, after the First World Congress in Sports Physical Therapy. 17 expert clinicians participated. 4 main sections were initially agreed upon, then participants elected to join 1 of the 4 groups—each group focused on 1 section of the consensus statement. Participants in each group discussed and summarised the key issues for their section before the 17-member group met again for discussion to reach consensus on the content of the 4 sections. Return to sport is not a decision taken in isolation at the end of the recovery and rehabilitation process. Instead, return to sport should be viewed as a continuum, paralleled with recovery and rehabilitation. Biopsychosocial models may help the clinician make sense of individual factors that may influence the athletes return to sport, and the Strategic Assessment of Risk and Risk Tolerance framework may help decision-makers synthesise information to make an optimal return to sport decision. Research evidence to support return to sport decisions in clinical practice is scarce. Future research should focus on a standardised approach to defining, measuring and reporting return to sport outcomes, and identifying valuable prognostic factors for returning to sport.

Electric Bicycles as a New Active Transportation Modality to Promote Health

UNLABELLED Electrically assisted bicycles (EAB) are an emerging transportation modality favored for environmental reasons. Some physical effort is required to activate the supporting engine, making it a potential active commuting option. PURPOSE We hypothesized that using an EAB in a hilly city allows sedentary subjects to commute comfortably, while providing a sufficient effort for health-enhancing purposes. METHODS Sedentary subjects performed four different trips at a self-selected pace: walking 1.7 km uphill from the train station to the hospital (WALK), biking 5.1 km from the lower part of town to the hospital with a regular bike (BIKE), or EAB at two different power assistance settings (EAB high, EAB std). HR, oxygen consumption, and need to shower were recorded. RESULTS Eighteen sedentary subjects (12 female, 6 male) age 36 ± 10 yr were included, with V·O 2max of 39.4 ± 5.4 mL·min(-1)·kg(-1). Time to complete the course was 22 (WALK), 19 (EAB high), 21 (EAB std), and 30 (BIKE) min. Mean %V·O 2max was 59.0%, 54.9%, 65.7%, and 72.8%. Mean %HRmax was 71.5%, 74.5%, 80.3%, and 84.0%. There was no significant difference between WALK and EAB high, but all other comparisons were different (P < 0.05). Two subjects needed to shower after EAB high, 3 needed to shower after WALK, 8 needed to shower after EAB std, and all 18 needed to shower after BIKE. WALK and EAB high elicited 6.5 and 6.1 METs (no difference), whereas it was 7.3 and 8.2 for EAB std and BIKE. CONCLUSIONS EAB is a comfortable and ecological transportation modality, helping sedentary people commute to work and meet physical activity guidelines. Subjects appreciated ease of use and mild effort needed to activate the engine support climbing hills, without the need to shower at work. EAB can be promoted in a challenging urban environment to promote physical activity and mitigate pollution issues.

Concomitant calcium entry blockade and inhibition of the renin-angiotensin system: a rational and effective means for treating hypertension

Pharmacological treatment of hypertension is effective in preventing cardiovascular and renal complications. Calcium antagonists (CAs) and blockers of the renin-angiotensin system [angiotensin-converting enzyme (ACE) inhibitors and angiotensin II antagonists (ARBs)] are widely used today to initiate antihypertensive treatment but, when given as monotherapy, do not suffice in most patients to normalise blood pressure (BP). Combining a CA and either an ACE-inhibitor or an ARB considerably increases the antihypertensive efficacy, but not at the expense of a deterioration of tolerability. Several fixed-dose combinations are available (CA + ACE-inhibitors: amlodipine + benazepril, felodipine + ramipril, verapamil + trandolapril; CA + ARB: amlodipine + valsartan). They are expected not only to improve BP control, but also to facilitate long-term adherence with ON antihypertensive therapy, thereby providing renal damage caused by high BP. maximal protection against the cardiovascular and renal damage caused by high BP.

Influence of Hip-Flexion Angle on Hamstrings Isokinetic Activity in Sprinters

CONTEXT Hamstrings strains are common and debilitating injuries in many sports. Most hamstrings exercises are performed at an inadequately low hip-flexion angle because this angle surpasses 70° at the end of the sprinting legs swing phase, when most injuries occur. OBJECTIVE To evaluate the influence of various hip-flexion angles on peak torques of knee flexors in isometric, concentric, and eccentric contractions and on the hamstrings-to-quadriceps ratio. DESIGN Descriptive laboratory study. SETTING Research laboratory. PATIENTS AND OTHER PARTICIPANTS Ten national-level sprinters (5 men, 5 women; age = 21.2 ± 3.6 years, height = 175 ± 6 cm, mass = 63.8 ± 9.9 kg). INTERVENTION(S) For each hip position (0°, 30°, 60°, and 90° of flexion), participants used the right leg to perform (1) 5 seconds of maximal isometric hamstrings contraction at 45° of knee flexion, (2) 5 maximal concentric knee flexion-extensions at 60° per second, (3) 5 maximal eccentric knee flexion-extensions at 60° per second, and (4) 5 maximal eccentric knee flexionextensions at 150° per second. MAIN OUTCOME MEASURE(S) Hamstrings and quadriceps peak torque, hamstrings-to-quadriceps ratio, lateral and medial hamstrings root mean square. RESULTS We found no difference in quadriceps peak torque for any condition across all hip-flexion angles, whereas hamstrings peak torque was lower at 0° of hip flexion than at any other angle (P < .001) and greater at 90° of hip flexion than at 30° and 60° (P < .05), especially in eccentric conditions. As hip flexion increased, the hamstrings-to-quadriceps ratio increased. No difference in lateral or medial hamstrings root mean square was found for any condition across all hip-flexion angles (P > .05). CONCLUSIONS Hip-flexion angle influenced hamstrings peak torque in all muscular contraction types; as hip flexion increased, hamstrings peak torque increased. Researchers should investigate further whether an eccentric resistance training program at sprint-specific hip-flexion angles (70° to 80°) could help prevent hamstrings injuries in sprinters. Moreover, hamstrings-to-quadriceps ratio assessment should be standardized at 80° of hip flexion.

Whole-body vibration training elevates creatine kinase levels in sedentary subjects

PRINCIPLES Whole body vibration (WBV) is an increasingly popular modality of muscle training, especially in sedentary subjects. We hypothesised that the vigorous muscle contractions elicited by WBV can cause muscle damage expressed as an elevation in muscle enzymes. METHODS Twenty inactive subjects, ten male and ten female, aged 22.7 ± 2.6, BMI 22.4 ± 2.1 were included based on the absence of regular physical activity as defined by international guidelines, and no history of recent trauma, musculoskeletal pathology, implanted prosthetics, cardiovascular disease or drug intake. The intervention consisted of one bout of high intensity WBV corresponding to a typical training session, involving all the major muscle groups. Plasma levels of muscle enzymes prior to and at 24, 48 and 96 hours post exercise (creatine kinase - CK, MB fraction, troponin I, aminotransferases and lactate dehydrogenase) were measured. In addition, blood lactate was assayed immediately after exercise. Delayed onset muscle soreness (DOMS) was evaluated using a visual analogical scale. RESULTS Five participants (25%) showed a significant increase in post exercise CK levels (> double of baseline). Maximal value was 3520 U/l. No change was observed in CK-MB or troponin I. Lactate increased to 10.0 ± 2.4 in men and 6.9 ± 2.4 in women. All participants had some degrees of DOMS, without correlation to enzymatic changes. DISCUSSION WBV can provoke high CK elevation in healthy, medication-free inactive subjects. Such an elevation is transient and harmless, but could be wrongly attributed to drug induced myopathy, as in patients treated with statins. Practitioners should bear this in mind before discontinuing a potential life saving drug.

Overspeed HIIT in Lower-Body Positive Pressure Treadmill Improves Running Performance.

PURPOSE Optimal high-intensity interval training (HIIT) regimens for running performance are unknown, although most protocols result in some benefit to key performance factors (running economy (RE), anaerobic threshold (AT), or maximal oxygen uptake (VO2max)). Lower-body positive pressure (LBPP) treadmills offer the unique possibility to partially unload runners and reach supramaximal speeds. We studied the use of LBPP to test an overspeed HIIT protocol in trained runners. METHODS Eleven trained runners (35 ± 8 yr, VO2max, 55.7 ± 6.4 mL·kg⁻¹·min⁻¹) were randomized to an LBPP (n = 6) or a regular treadmill (CON, n = 5), eight sessions over 4 wk of HIIT program. Four to five intervals were run at 100% of velocity at VO2max (vVO2max) during 60% of time to exhaustion at vVO2max (Tlim) with a 1:1 work:recovery ratio. Performance outcomes were 2-mile track time trial, VO2max, vVO2max, vAT, Tlim, and RE. LBPP sessions were carried out at 90% body weight. RESULTS Group-time effects were present for vVO2max (CON, 17.5 vs. 18.3, P = 0.03; LBPP, 19.7 vs. 22.3 km·h⁻¹; P < 0.001) and Tlim (CON, 307.0 vs. 404.4 s, P = 0.28; LBPP, 444.5 vs. 855.5, P < 0.001). Simple main effects for time were present for field performance (CON, -18; LBPP, -25 s; P = 0.002), VO2max (CON, 57.6 vs. 59.6; LBPP, 54.1 vs. 55.1 mL·kg⁻¹·min⁻¹; P = 0.04) and submaximal HR (157.7 vs. 154.3 and 151.4 vs. 148.5 bpm; P = 0.002). RE was unchanged. CONCLUSIONS A 4-wk HIIT protocol at 100% vVO2max improves field performance, vVO2max, VO2max and submaximal HR in trained runners. Improvements are similar if intervals are run on a regular treadmill or at higher speeds on a LPBB treadmill with 10% body weight reduction. LBPP could provide an alternative for taxing HIIT sessions.

Bilateral symmetry of radial pulse in high-level tennis players: implications for the validity of central aortic pulse wave analysis

Background Reconstruction of the central aortic pressure wave from the noninvasive recording of the radial pulse with applanation tonometry has become a standard tool in the field of hypertension. It is not presently known whether recording the radial pulse on the dominant or the nondominant side has any effect on such reconstruction. Method We carried out radial applanation tonometry on both forearms in young, healthy, male volunteers, who were either sedentary (n = 11) or high-level tennis players (n = 10). The purpose of including tennis players was to investigate individuals with extreme asymmetry between the dominant and nondominant upper limb. Results In the sedentary individuals, forearm circumference and handgrip strength were slightly larger on the dominant (mean ± SD respectively 27.9 ± 1.5 cm and 53.8 ± 10 kg) than on nondominant side (27.3 ± 1.6 cm, P < 0.001 vs. dominant, and 52.1 ± 11 kg, P = NS). In the tennis players, differences between sides were more conspicuous (forearm circumference: dominant 28.0 ± 1.7 cm nondominant 26.4 ± 1.5 cm, P < 0.001; handgrip strength 61.4 ± 10.8 vs. 53.4 ± 9.7 kg, P < 0.001). We found that in both sedentary individuals and tennis players, the radial pulse had identical shape on both sides and, consequently, the reconstructed central aortic pressure waveforms, as well as derived indices of central pulsatility, were not dependent on the side where applanation tonometry was carried out. Conclusion Evidence from individuals with maximal asymmetry of dominant vs. nondominant upper limb indicates that laterality of measurement is not a methodological issue for central pulse wave analysis carried out with radial applanation tonometry.

Whole-body vibration training: Metabolic cost of synchronous, side-alternating or no vibrations

Abstract Whole-body vibration training improves strength and can increase maximal oxygen consumption ([Vdot]O2max). No study has compared the metabolic demand of synchronous and side-alternating whole-body vibration. We measured [Vdot]O2 and heart rate during a typical synchronous or side-alternating whole-body vibration session in 10 young female sedentary participants. The 20-min session consisted of three sets of six 45-s exercises, with 15 s recovery between exercises. Three conditions wererandomly tested on separate days: synchronous at 35 Hz and 4 mm amplitude, side-alternating at 26 Hz and 7.5 mm amplitude (peak acceleration matched at 20 g in both vibration conditions), and no vibrations. Mean [Vdot]O2 (expressed as %[Vdot]O2max) did not differ between conditions: 29.7 ± 4.2%, 32.4 ± 6.5%, and 28.7 ± 6.7% for synchronous, side-alternating, and no vibrations respectively (P = 0.103). Mean heart rate (% maximal heart rate) was 65.6 ± 7.3%, 69.8 ± 7.9%, and 64.7 ± 5.6% for synchronous, side-alternating, and no vibrations respectively, with the side-alternating vibrations being significantly higher (P = 0.019). When analysing changes over exercise sessions, mean [Vdot]O2 was higher for side-alternating (P < 0.001) than for synchronous and no vibrations. In conclusion, side-alternating whole-body vibration elicits higher heart rate responses than synchronous or no vibrations, and could elevate [Vdot]O2, provided the session lasts more than 20 min.

Predictive Factors for Vitamin D Concentrations in Swiss Athletes: A Cross-sectional Study

Vitamin D concentrations corresponding to 75 nmol/L 25(OH)D have been associated with maintained muscle function, growth and regeneration, optimal bone health and immunology in athletes. The objective of this study was to investigate the prevalence and predictors of insufficient 25(OH)D concentrations in athletes. Six hundred three Swiss athletes were assessed. 25(OH)D was analysed by high-performance liquid chromatography (HPLC). A standardized questionnaire was used to gather information about potential predictors for 25(OH)D concentrations; 50.5% showed insufficient 25(OH)D concentrations. Differences in predicted probability of insufficient 25(OH)D were found for those vitamin D supplemented (42%) versus not supplemented (52%), in those performing indoor (58%) versus outdoor sports (43%), and during the sun-deprived seasons of fall (49%), winter (70%) and spring (57%) compared with summer (17%). Higher BMI z-scores and age were associated with higher 25(OH)D concentrations. In conclusion, insufficient 25(OH)D concentrations were common among athletes especially at a younger age, among those not supplemented, in athletes who trained indoors, and during the sun-deprived seasons. Because the prevalence of insufficient 25(OH)D concentrations in this study was high, regular supplementation in athletes may be indicated, except perhaps during the summer season. Further research is needed to determine which 25(OH)D concentrations lead to optimal health and performance in athletes.

Infographic: 2016 Consensus statement on return to sport from the First World Congress in Sports Physical Therapy, Bern

Infographic: 2016 Consensus statement on return to sport from the First World Congress in Sports Physical Therapy, Bern