The Physiological Profile Following Two Popular Cold Interventions After Activity in Hot and Humid Environment.

This research aims to describe and compare the effects of partial-body cryotherapy (PBC) and cold-water immersion (CWI) on the physiological responses of soccer players after cycling in a hot and humid environment. Sixteen elite soccer players participated in three experiments, and received CWI (13°C for 15 min), PBC (110°C-140°C for 3 min), and CON (room temperature: 21°C ± 2°C), respectively, after aerobic and anaerobic cycling in a hot and humid environment (temperature: 35°C-38°C; humidity: 60%-70%). Heart rate (HR), blood lactate (BLa-), perfusion index (PI), oxygen saturation (SaO2), core temperature (Tc), skin temperature (Ts), and rating of perceived exertion (RPE) were assessed at baseline and through 20 min (5-min intervals). HR was lower in CWI than CON after 20 min (p < .05). SaO2 was higher in CWI than PBC and CON between 10 and 20 min (p < .05). Tc was lower from CWI and PBC than CON between 10 and 20 min (p < .05). Ts was lower in PBC than CWI between 15 and 20 min (p < .05). RPE was lower in PBC than CON 20 min after the exercise (p < .05). No main group differences for BLa- and PI were observed. The physiological effects of PBC are generally similar to CWI. Compared with CON, both CWI and PBC could promote the recovery of physiological indexes within 20 min of exercise in a hot and humid environment. However, PBC can lead to a decrease in SaO2 due to excessive nitrogen inhalation.

Cryostimulation for Post-exercise Recovery in Athletes: A Consensus and Position Paper.

Recovery after exercise is a crucial key in preventing muscle injuries and in speeding up the processes to return to homeostasis level. There are several ways of developing a recovery strategy with the use of different kinds of traditional and up-to-date techniques. The use of cold has traditionally been used after physical exercise for recovery purposes. In recent years, the use of whole-body cryotherapy/cryostimulation (WBC; an extreme cold stimulation lasting 1-4 min and given in a cold room at a temperature comprised from -60 to -195°C) has been tremendously increased for such purposes. However, there are controversies about the benefits that the use of this technique may provide. Therefore, the main objectives of this paper are to describe what is whole body cryotherapy/cryostimulation, review and debate the benefits that its use may provide, present practical considerations and applications, and emphasize the need of customization depending on the context, the purpose, and the subject's characteristics. This review is written by international experts from the working group on WBC from the International Institute of Refrigeration.

Cold water immersion settings for reducing muscle tissue temperature: a linear dose-response relationship.

BACKGROUND: Although cold water immersion (CWI) is widely accepted and integrated as a recovery modality in sports practice, questions regarding its proposed working mechanisms remain. This study systematically reviews the existing literature on one the proposed mechanisms of CWI, its effect on muscle tissue temperature, and subsequently tries to identify a dose-response relationship in order to describe an optimal dose. EVIDENCE ACQUISITION: A systematic literature search (PubMed and Sport Discus) was conducted in October 2017. Dose-response relationships were analyzed using linear regression while controlling for possible confounders (muscle measurement depth and immersion position). EVIDENCE SYNTHESIS: A total of 10 studies, with a total of 104 participants, were included utilizing 26 different CWI protocols. Muscle tissue temperatures were reduced significantly by 24 CWI protocols. A significant, relationship with a medium effect size (r=0.51) was identified between muscle tissue temperature and CWI. The most optimal dose-response relationship, with a large effect size, (r=0.87) was described for CWI protocols using full-body immersion at a measurement depth of 30 mm (y = 4.051 x + 0.535). CONCLUSIONS: CWI can decrease muscle tissue temperature significantly if a minimum CWI dose of 1.1 is applied, corresponding with an immersion of 11 minutes with a water temperature of 10 °C.

Systematic development of a tennis injury prevention programme.

INTRODUCTION: Despite an injury incidence of up to 3.0/1000 hours of play, there are no published tennis injury prevention programmes. This article aims to describe the developmental process of TennisReady, an e-health tennis-specific injury programme for adult recreational tennis players. FIVE-STEP APPROACH: A bottom-up, five-step approach was used with the Knowledge Transfer Scheme as a guideline. During the first step, a problem statement among targeted users was carried out. 475 (partially) completed surveys and group interviews (n=8) revealed a preference for an app-based prevention intervention of 10-15 min. As a second step, a systematic review was performed to identify prevention strategies in tennis. None were found. In step 3, during two expert group meetings (n=18), the findings of the first two steps were discussed and goals were formulated. Relevant and potential exercises for the programme were discussed. A subgroup of a total of six physical therapists, physicians and trainers developed the content of the programme in step 4. Step 5 included an evaluation of the exercises in 33 recreational tennis players. Participants evaluated the exercises during training sessions with trainers involved in the programme's development or their colleagues. Participants evaluated the programme through standardised surveys or group interviews. Based on this evaluation, the programme was adjusted by altering exercises and frequencies, and it was evaluated in a second target group (n=27). The second evaluation did not result in any major changes to the final prevention programme. CONCLUSION: Through a five-step approach guided by the Knowledge Transfer Scheme, we developed an e-health tennis-specific prevention programme for adult tennis players. This 10 min intervention will require testing in a randomised controlled setting.

A customised cold-water immersion protocol favours one-size-fits-all protocols in improving acute performance recovery.

The purpose of the present study was to investigate whether a customised cold-water immersion (CWIc) protocol was more effective in enhancing acute performance recovery than a one-size-fits-all CWI (CWIs) or active recovery (AR) protocol. On three separate testing days, 10 healthy, physically active, non-smoking males completed the same fatiguing protocol (60 squat jumps and a 2'30″ all-out cycling time-trial) followed by CWIc (12°C, 10-17 min), CWIs (15°C, 10 min) or AR (60 W, 10 min). Outcome measures to assess acute recovery were heart rate variability (HRV) as HRVrecovery, muscle power (MP) as absolute and relative decline, and muscle soreness (MS) at 0 and 24 h. HRVrecovery for CWIc was significantly higher compared to CWIs (p = .026, r = 0.74) and AR (p = .000, r = 0.95). The relative decline in MP after CWIc was significantly lower than after CWIs (p = .017, r = 0.73). MS 0 h and MS 24 h post-intervention were not different after CWIc compared to CWIs and AR (p > .05). The findings of the present study demonstrated that CWIc outperforms CWIs and AR in the acute recovery of cardiovascular (HRV) and CWIs in neuromuscular (MP) performance with no differences in MS. To optimise the effects of CWI, contributions of the protocol duration and water temperature should be considered to guarantee an optimal customised dose.

Effectiveness of an occupational health intervention program to reduce whole body vibration exposure: an evaluation study with a controlled pretest-post-test design.

BACKGROUND: An effective intervention program aiming to reduce whole body vibration (WBV) exposure at work will reduce the number of low back complaints in the near future. METHODS: An evaluation study with a controlled pretest-post-test design. Nine companies and 126 drivers were included in the study. Cluster randomization on company level divided the drivers and their employers in an intervention group and a "care-as-usual" group. At baseline (T0) and intervention program was implemented and evaluated after 7 months (T1). The main outcome measure was WBV exposure. Process measures included knowledge, attitude, and (intended) behavior towards reduction of WBV exposure for the drivers and knowledge and WBV policy for the employers. RESULTS: At T1, no significant reduction was found in WBV exposure within both groups compared with T0. CONCLUSIONS: Probably due to poor to moderate compliance, the intervention program was not effective in reducing the WBV exposure on group level but small reductions in WBV exposure are possible when intervention compliance is high.

Risk factors for developing jumper's knee in sport and occupation: a review.

BACKGROUND: The onset of jumper's knee is generally associated with sports and sporting activities. Employees in certain professions might be at risk as well for developing jumper's knee. Therefore, it is of interest to identify risk factors in sport and/or occupation. FINDINGS: A systematic search of the international scientific literature was performed until November 2008 in the scientific databases (a) Medline, (b) Embase, and (c) SportDiscus. All types of studies were included. The search strategy retrieved ten articles about risk factors in sport that met the inclusion criteria. Risk factors that could be identified are; playing volleyball (4 studies), playing basketball (3 studies), training and playing volleyball/basketball more than 12 hours per week (2 studies), in combination with weight-bearing activities of at least 5 hours per week (1 study) and playing or training on a hard surface (1 study). No studies were found regarding occupation that fulfilled the inclusion criteria. CONCLUSION: Playing volleyball and basketball has a positive association with the onset or worsening of jumper's knee. Other risk factors are training and playing hours of at least 12 hours per week and/or in combination with weight training of at least 5 hours per week, and/or with playing or training on a hard surface. We did not find a specific occupational risk factor.

A comparison of the activity profile and physiological demands between advanced and recreational veteran tennis players.

The aim of the study was to examine whether differences in playing level influence the activity profile and physiological demands of advanced and recreational veteran men's tennis players during an hour of tennis match play. Ten advanced (International Tennis Number [ITN] 3-5, 45.3 +/- 5.1 years) and 10 recreational (ITN 7-9, 44.8 +/- 4.7 years) veteran men's tennis players participated in 4 experimental sessions: (1) an ITN on-court assessment, (2) a laboratory incremental treadmill test, (3) an hour of simulated tennis match play, and (4) 30 minutes of tennis match play using a portable gas analyzer. Subjects' VO2 and heart rate (HR) were recorded by portable analyzers. Moreover, energy expenditure was evaluated by indirect calorimetry. Temporal structure and distance covered were determined from video recordings. Subjects' VO2 (24.5 +/- 4.1 vs. 23.3 +/- 3 ml x kg x min), HR (148.3 +/- 11.5 vs. 149.8 +/- 8.4 bpm), duration of rallies (DR) (6.3 +/- 4.1 vs. 7.6 +/- 5.5 seconds), and effective playing time (EPT) (21.7 +/- 5.0 vs. 23.6 +/- 5.4%), HR (148.3 +/- 11.5 vs. 149.8 +/- 8.4 bpm), and energy expenditure (263.1 +/- 49.4 and 281.3 +/- 61.8 kcal x min) during play did not differ significantly (p > 0.05) between advanced and recreational players. The advanced players covered significantly more meters than the recreational players during their 1-hour tennis matches (mean +/- SD: 3568.8 +/- 532.2 vs. 3173.8 +/- 226 m, p < 0.01) at lower running speeds. The results indicate that, independently of ability, tennis match play satisfies the American College of Sports Medicine recommendations for quantity and quality of exercise for the development and maintenance of cardiovascular fitness in healthy adults and seems to be a viable and highly popular mode of healthy activity.

Does body mass index increase the risk of low back pain in a population exposed to whole body vibration?

The aim of this study was to determine whether body mass index (BMI) influences the risk of low back pain (LBP) in a population exposed to whole body vibration (WBV). For this a self-administered questionnaire was sent to 467 participants, driving occupational vehicles. Vibration measurements were performed according to ISO 2631-1 on a representative sample (n=30) of this population. For each participant, we calculated the current root mean square (r.m.s.) over an 8 h (A(8)) working day. The questionnaire response rate was 47% (n=221). We did not find a significant correlation between BMI and the onset of LBP in the last 7 days (r=0.07, p=0.34) nor for LBP in past 12 months (r=-0.30, p=0.63). No significant increased risk was found for the onset of LBP with the increase of BMI, neither for the last 7 days (OR 1.02; 95% CI: 0.93-1.23) nor for the past 12 months LBP (OR 0.98; 95% CI: 0.89-1.09). Introducing the interaction with WBV exposure in the logistic regression model, did not result a significant increased risk in the onset of LBP-7 days (OR 0.97; 95% CI: 0.92-1.01) nor in the onset of LBP 12 months (OR 0.97; 95% CI: 0.93-1.01) either. Occupational participants exposed to WBV, with a high BMI do not have an increased risk for the development of LBP.

The development of an intervention programme to reduce whole-body vibration exposure at work induced by a change in behaviour: a study protocol.

BACKGROUND: Whole body vibration (WBV) exposure at work is common and studies found evidence that this exposure might cause low back pain (LBP). A recent review concluded there is a lack of evidence of effective strategies to reduce WBV exposure. Most research in this field is focussed on the technical implications, although changing behaviour towards WBV exposure might be promising as well. Therefore, we developed an intervention programme to reduce WBV exposure in a population of drivers with the emphasis on a change in behaviour of driver and employer. The hypothesis is that an effective reduction in WBV exposure, in time, will lead to a reduction in LBP as WBV exposure is a proxy for an increased risk of LBP. METHODS/DESIGN: The intervention programme was developed specifically for the drivers of vibrating vehicles and their employers. The intervention programme will be based on the most important determinants of WBV exposure as track conditions, driving speed, quality of the seat, etc. By increasing knowledge and skills towards changing these determinants, the attitude, social influence and self-efficacy (ASE) of both drivers and employers will be affected having an effect on the level of exposure. We used the well-known ASE model to develop an intervention programme aiming at a change or the intention to change behaviour towards WBV exposure. The developed programme consists of: individual health surveillance, an information brochure, an informative presentation and a report of the performed field measurements. DISCUSSION: The study protocol described is advantageous as the intervention program actively tries to change behaviour towards WBV exposure. The near future will show if this intervention program is effective by showing a decrease in WBV exposure.

Increased hypoxic ventilatory response during 8 weeks at 3800 m altitude.

Acclimatization to chronic hypoxia (CH) increases ventilation (V(I)) and the isocapnic hypoxic ventilatory response (HVR) over 2-14 days but hypoxic desensitization blunts the HVR after years of CH. We tested for hypoxic desensitization during the first 2 months of CH by studying five normal subjects at sea level (SL) and for 8 weeks at 3800 m (CH, PI(O(2)) approximately 90 Torr). We measured the isocapnic HVR (Delta V(I)/Delta Sa(O(2)) and tested for hypoxic ventilatory decline (HVD) by stepping Sa(O(2)) to 80% after 14 min at 90%. The HVR increased significantly after 2 days and remained significantly elevated for 8 weeks of CH. HVD was similar at SL and during 8 weeks of CH. Hence, hypoxic desensitization of the HVR does not occur after only 8 weeks of hypoxia and the increased HVR during this time does not involve changes in HVD.

Persistence of the lactate paradox over 8 weeks at 3,800 m.

The arterial blood lactate [La] response to exercise increases in acute hypoxia, but returns to near the normoxic (sea level, SL) response after 2 to 5 weeks of altitude acclimatization. Recently, it has been suggested that this gradual return to the SL response in [La], known as the lactate paradox (LP), unexpectedly disappears after 8 to 9 weeks at altitude. We tested this idea by recording the [La] response to exercise every 2 weeks over 8 weeks at altitude. Five normal, fit SL-residents were studied at SL and 3,800 m (Pbar = 485 torr) in both normoxia (PIO2 = 150 torr) and hypoxia (PIO2 = 91 torr approximately air at 3,800 m). Arterial [La] and blood gas values were determined at rest and during cycle exercise at the same absolute workloads (0, 25, 50, 75, 90, and 100% of initial SL-VO2Max) and exercise duration (4, 4, 4, 2, 1.5, and 0.75 min, respectively) at each time point. [La] curves were elevated in acute hypoxia at SL (p < 0.01) and at 3,800 m fell progressively toward the SL-normoxic curve (p < 0.01). On the same days, [La] responses in acute normoxia showed essentially no changes over time and were similar to initial SL normoxic responses. We also measured arterial catecholamine levels at each load and found a close relationship to [La] over time, supporting a role for adrenergic influence on [La]. In summary, extending the time at this altitude to 8 weeks produced no evidence for reversal of the LP, consistent with prior data obtained over shorter periods of altitude residence.