Lack of a Dose Response from 7 Days of Ischemic Preconditioning in Moderately trained Cyclists

Effects of Recurring IPC vs. rIPC Maneuvers on Exercise Performance, Pulse Wave Velocity, and Red Blood Cell Deformability: Special Consideration of Reflow Varieties

Beneficial effects of (remote) ischemia preconditioning ((r)IPC), short episodes of blood occlusion and reperfusion, are well-characterized, but there is no consensus regarding the effectiveness of (r)IPC on exercise performance. Additionally, direct comparisons of IPC and rIPC but also differences between reflow modes, low reflow (LR) and high reflow (HR) in particular, are lacking, which were thus the aims of this study. Thirty healthy males conducted a performance test before and after five consecutive days with either IPC or rIPC maneuvers (n = 15 per group). This procedure was repeated after a two-week wash-out phase to test for both reflow conditions in random order. Results revealed improved exercise parameters in the IPC LR and to a lesser extent in the rIPC LR intervention. RBC deformability increased during both rIPC LR and IPC LR, respectively. Pulse wave velocity (PWV) and blood pressures remained unaltered. In general, deformability and PWV positively correlated with performance parameters. In conclusion, occlusion of small areas seems insufficient to affect large remote muscle groups. The reflow condition might influence the effectiveness of the (r)IPC intervention, which might in part explain the inconsistent findings of previous investigations. Future studies should now focus on the underlying mechanisms to explain this finding.

Testing, Training, and Optimising Performance of Track Cyclists: A Systematic Mapping Review

Background

Track cyclists must develop mental, physical, tactical and technical capabilities to achieve success at an elite level. Given the importance of these components in determining performance, it is of interest to understand the volume of evidence to support implementation in practice by coaches, practitioners, and athletes.

Objective

The aim of this study was to conduct a systematic mapping review to describe the current scale and density of research for testing, training and optimising performance in track cycling.

Methods

All publications involving track cyclist participants were reviewed from four databases (PubMed, SPORTDiscus, Academic Search Complete, Cochrane Library) plus additional sources. Search results returned 4019 records, of which 71 met the inclusion criteria for the review.

Results

The review revealed most published track cycling research investigated athlete testing followed by performance optimisation, with training being the least addressed domain. Research on the physical components of track cycling has been published far more frequently than for tactical or technical components, and only one study was published on the mental components of track cycling. No true experimental research using track cyclists has been published, with 51 non-experimental and 20 quasi-experimental study designs.

Conclusions

Research in track cycling has been growing steadily. However, it is evident there is a clear preference toward understanding the physical—rather than mental, tactical, or technical—demands of track cycling. Future research should investigate how this aligns with coach, practitioner, and athlete needs for achieving track cycling success.

Registration

This systematic mapping review was registered on the Open Science Framework (osf.io/wt7eq).

Supplementary Information

The online version contains supplementary material available at 10.1007/s40279-021-01565-z.

Neuromuscular Adjustments Following Sprint Training with Ischemic Preconditioning in Endurance Athletes: Preliminary Data

This preliminary study examined the effect of chronic ischemic preconditioning (IPC) on neuromuscular responses to high-intensity exercise. In a parallel-group design, twelve endurance-trained males (VO2max 60.0 ± 9.1 mL·kg-1·min-1) performed a 30-s Wingate test before, during, and after 4 weeks of sprint-interval training. Training consisted of bi-weekly sessions of 4 to 7 supra-maximal all-out 30-s cycling bouts with 4.5 min of recovery, preceded by either IPC (3 × 5-min of compression at 220 mmHg/5-min reperfusion, IPC, n = 6) or placebo compressions (20 mmHg, PLA, n = 6). Mechanical indices and the root mean square and mean power frequency of the electromyographic signal from three lower-limb muscles were continuously measured during the Wingate tests. Data were averaged over six 5-s intervals and analyzed with Cohen's effect sizes. Changes in peak power output were not different between groups. However, from mid- to post-training, IPC improved power output more than PLA in the 20 to 25-s interval (7.6 ± 10.0%, ES 0.51) and the 25 to 30-s interval (8.8 ± 11.2%, ES 0.58), as well as the fatigue index (10.0 ± 2.3%, ES 0.46). Concomitantly to this performance difference, IPC attenuated the decline in frequency spectrum throughout the Wingate (mean difference: 14.8%, ES range: 0.88-1.80). There was no difference in root mean square amplitude between groups. These preliminary results suggest that using IPC before sprint training may enhance performance during a 30-s Wingate test, and such gains occurred in the last 2 weeks of the intervention. This improvement may be due, in part, to neuromuscular adjustments induced by the chronic use of IPC.

Effect of 2-Weeks Ischemic Preconditioning on Exercise Performance: A Pilot Study

An acute bout of ischemic preconditioning (IPC) has been reported to increase exercise performance. Nevertheless, the ineffectiveness of acute IPC on exercise performance has also been reported. Similarly, the effect of a shot-term intervention of IPC on exercise performance remains controversial in previous studies. In this study, we examined the effects of short-term IPC intervention on whole and local exercise performances and its-related parameters. Ten healthy young males undertook a 2-weeks IPC intervention (6 days/weeks). The IPC applied to both legs with three episodes of a 5-min ischemia and 5-min reperfusion cycle. Whole-body exercise performance was assessed by peak O₂ consumption (VO₂: VO_2peak) during a ramp-incremental cycling test. Local exercise performance was assessed by time to task failure during a knee extensor sustained endurance test. A repeated moderate-intensity cycling test was performed to evaluate dynamics of pulmonary VO₂ and muscle deoxygenation. The knee extensor maximal voluntary contraction and quadriceps femoris cross-sectional area measurements were performed to explore the potentiality for strength gain and muscle hypertrophy. The whole-body exercise performance (i.e., VO_2peak) did not change before and after the intervention (P = 0.147, Power = 0.09, Effect size = 0.21, 95% confidence interval: −0.67, 1.09). Moreover, the local exercise performance (i.e., time to task failure) did not change before and after the intervention (P = 0.923, Power = 0.05, Effect size = 0.02, 95% confidence interval: −0.86, 0.89). Furthermore, no such changes were observed for all parameters measured using a repeated moderate-intensity cycling test and knee extensor strength and quadriceps femoris size measurements. These findings suggest that a 2-weeks IPC intervention cannot increase whole-body and local exercise performances, corresponding with ineffectiveness on its-related parameters in healthy young adults. However, the statistical analyses of changes in the measured parameters in this study showed insufficient statistical power and sensitivity, due to the small sample size. Additionally, this study did not include control group(s) with placebo and/or nocebo. Therefore, further studies with a larger sample size and control group are required to clarify the present findings.

Effects of different ischemic preconditioning occlusion pressures on muscle damage induced by eccentric exercise: a study protocol for a randomized controlled placebo clinical trial

Introduction

Due to its greater generation of muscle strength and less metabolic demand, eccentric exercise has been widely used in rehabilitation and for improving physical fitness. However, eccentric exercise can induce muscle damage by providing structural changes and reduced muscle function, so even with the protection caused by the repeated bout effect from eccentric exercise, it is necessary to seek alternatives to reduce this damage caused by stress. Thus, ischemic preconditioning could represent an aid to reduce the damage muscle or increase the protective effect caused by eccentric exercise.

Objectives

To compare the effects of ischemic preconditioning, using different occlusion pressures, on acute and delayed responses to perceptual outcomes, markers of muscle damage, and performance in post-eccentric exercise recovery.

Methods

A randomized controlled placebo clinical trial will be carried out with 80 healthy men aged 18 to 35 years who will be randomly divided into four groups: ischemic preconditioning using total occlusion pressure, ischemic preconditoning with 40% more than total occlusion pressure, placebo (10 mmHg), and control. The ischemic preconditioning protocol will consist of four cycles of ischemia and reperfusion of five minutes each. All groups will perform an eccentric exercise protocol, and assessments will be carried out before, immediately after, and 24, 48, 72, and 96 h after the end of the eccentric exercise to evaluate creatine kinase, blood lactate, perception of recovery using the Likert scale, being sequentially evaluated, pain by the visual analog scale, pain threshold using a pressure algometer, muscle thickness by ultrasound, muscle tone, stiffness and elasticity by myotonometry, vectors of cell integrity through electrical bioimpedance, and maximal voluntary isometric contraction using the isokinetic dynamometer. The trial was registered at ClinicalTrials.gov (NCT04420819).

Discussion

The present study aims to present an alternative technique to reduce muscle damage caused by eccentric exercise, which is easy to apply and low cost. If the benefits are proven, ischemic preconditioning could be used in any clinical practice that aims to minimize the damage caused by exercise, presenting an advance in the prescription of eccentric exercise and directly impacting on the results of post-exercise recovery.

Trial registration

ClinicalTrials.gov NCT04420819. Registered on 19 May 2020; Last update 24 March 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05285-7.

Ischemic Preconditioning Enhances Aerobic Adaptations to Sprint-Interval Training in Athletes Without Altering Systemic Hypoxic Signaling and Immune Function

Optimizing traditional training methods to elicit greater adaptations is paramount for athletes. Ischemic preconditioning (IPC) can improve maximal exercise capacity and up-regulate signaling pathways involved in physiological training adaptations. However, data on the chronic use of IPC are scarce and its impact on high-intensity training is still unknown. We investigated the benefits of adding IPC to sprint-interval training (SIT) on performance and physiological adaptations of endurance athletes. In a randomized controlled trial, athletes included eight SIT sessions in their training routine for 4 weeks, preceded by IPC (3 × 5 min ischemia/5 min reperfusion cycles at 220 mmHg, n = 11) or a placebo (20 mmHg, n = 9). Athletes were tested pre-, mid-, and post-training on a 30 s Wingate test, 5-km time trial (TT), and maximal incremental step test. Arterial O2 saturation, heart rate, rate of perceived exertion, and quadriceps muscle oxygenation changes in total hemoglobin (Δ[THb]), deoxyhemoglobin (Δ[HHb]), and tissue saturation index (ΔTSI) were measured during exercise. Blood samples were taken pre- and post-training to determine blood markers of hypoxic response, lipid-lipoprotein profile, and immune function. Differences within and between groups were analyzed using Cohen's effect size (ES). Compared to PLA, IPC improved time to complete the TT (Mid vs. Post: -1.6%, Cohen's ES ± 90% confidence limits -0.24, -0.40;-0.07) and increased power output (Mid vs. Post: 4.0%, ES 0.20, 0.06;0.35), Δ[THb] (Mid vs. Post: 73.6%, ES 0.70, -0.15;1.54, Pre vs. Post: 68.5%, ES 0.69, -0.05;1.43), Δ[HHb] (Pre vs. Post: 12.7%, ES 0.24, -0.11;0.59) and heart rate (Pre vs. Post: 1.4%, ES 0.21, -0.13;0.55, Mid vs. Post: 1.6%, ES 0.25, -0.09;0.60). IPC also attenuated the fatigue index in the Wingate test (Mid vs. Post: -8.4%, ES -0.37, -0.79;0.05). VO2peak and maximal aerobic power remained unchanged in both groups. Changes in blood markers of the hypoxic response, vasodilation, and angiogenesis remained within the normal clinical range in both groups. We concluded that IPC combined with SIT induces greater adaptations in cycling endurance performance that may be related to muscle perfusion and metabolic changes. The absence of elevated markers of immune function suggests that chronic IPC is devoid of deleterious effects in athletes, and is thus a safe and potent ergogenic tool.