Metabolic and Cardiovascular Responses to Upright Cycle Exercise with Leg Blood Flow Reduction

The purpose of this study was to examine the metabolic and cardiovascular response to exercise without (CON) or with (BFR) restricted blood flow to the muscles. Ten young men performed upright cycle exercise at 20, 40, and 60% of maximal oxygen uptake, VO₂max in both conditions while metabolic and cardiovascular parameters were determined. Pre-exercise VO₂ was not different between CON and BFR. Cardiac output (Q) was similar between the two conditions as a 25% reduction in stroke volume (SV) observed in BFR was associated with a 23% higher heart rate (HR) in BFR compared to CON. As a result rate-pressure product (RPP) was higher in the BFR but there was no difference in mean arterial pressure (MAP) or total peripheral resistance (TPR). During exercise, VO₂ tended to increase with BFR (~10%) at each workload. Q increased in proportion to exercise intensity and there were no differences between conditions. The increase in SV with exercise was impaired during BFR; being ~20% lower in BFR at each workload. Both HR and RPP were significantly greater at each workload with BFR. MAP and TPR were greater with BFR at 40 and 60% VO₂max. In conclusion, the BFR employed impairs exercise SV but central cardiovascular function is maintained by an increased HR. BFR appears to result in a greater energy demand during continuous exercise between 20 and 60% of control VO₂max; probably indicated by a higher energy supply and RPP. When incorporating BFR, HR and RPP may not be valid or reliable indicators of exercise intensity.

Key points

• Blood flow reduction (BFR) employed impairs stroke volume (SV) during exercise, but central cardiovascular function is maintained by an increased heart rate (HR).
• BFR appears to result in a greater energy demand during continuous exercise between 20 and 60% of control VO₂max;
• Probably indicated by a higher energy supply (VO₂) and rate-pressure product (HR x systolic blood pressure).

Key words: Aerobic exercise, doppler echocardiography, apparent exercise intensity, occlusion     

Cardiorespiratory and Metabolic Responses to Loaded Half Squat Exercise Executed at an Intensity Corresponding to the Lactate Threshold

This study was designed to identify the blood lactate threshold (LT2) for the half squat (HS) and to examine cardiorespiratory and metabolic variables during a HS test performed at a work intensity corresponding to the LT2. Twenty-four healthy men completed 3 test sessions. In the first, their one-repetition maximum (1RM) was determined for the HS. In the second session, a resistance HS incremental-load test was performed to determine LT2. Finally, in the third session, subjects performed a constant-load HS exercise at the load corresponding to the LT2 (21 sets of 15 repetitions with 1 min of rest between sets). In this last test, blood samples were collected for lactate determination before the test and 30 s after the end of set (S) 3, S6, S9, S12, S15, S18 and S21. During the test, heart rate (HR) was telemetrically monitored and oxygen consumption (VO₂), carbon dioxide production (VCO₂), minute ventilation (VE), respiratory exchange ratio (RER), ventilatory equivalent for O₂ (VE·VO₂^-1) and ventilatory equivalent for CO₂ (VE·VCO₂^-1) were monitored using a breath-by-breath respiratory gas analyzer. The mean LT2 for the participants was 24.8 ± 4.8% 1RM. Blood lactate concentrations showed no significant differences between sets 3 and 21 of exercise (p = 1.000). HR failed to vary between S6 and S21 (p > 1.000). The respiratory variables VO₂, VCO₂, and VE·VCO₂^-1 stabilized from S3 to the end of the constant-load HS test (p = 0.471, p = 0.136, p = 1.000), while VE and VE·VO₂^-1 stabilized from S6 to S21. RER did not vary significantly across exercise sets (p = 0.103). The LT2 was readily identified in the incremental HS test. Cardiorespiratory and metabolic variables remained stable during this resistance exercise conducted at an exercise intensity corresponding to the LT2. These responses need to be confirmed for other resistance exercises and adaptations in these responses after a training program also need to be addressed.

Key points

• It can be identified lactate threshold at half-squat.
• Exercise intensity is predominantly aerobic.
• The duration of the half-squat can be maintained over time, ~30 min of discontinuous exercise (21 sets, 15 repetitions, 1 min rest).
• Lactate threshold intensity may be suitable for older adults, sedentary individuals, patients or subjects with a lower functional capacity and even for resistance sports athletes.

Key words: Aerobic fitness/VO_2max, anaerobic threshold, exercise physiology, strength training     

Maximal and Submaximal Cardiorespiratory Responses to a Novel Graded Karate Test

The present study aimed to propose and assess the physiological responses of a novel graded karate test. Ten male national-level karate athletes (age 26 ± 5 yrs; body mass 69.5 ± 11.6 kg; height 1.70 ± 0.09 m) performed two exercise tests (separated by 2-7 days): 1) a running-based cardiopulmonary exercise test; 2) a graded karate test. The cardiopulmonary exercise test was comprised of an individualized ramp protocol for treadmill running, and the graded karate test was comprised of a sequence of ‘kisami-gyaku-zuki” punching at a fixed frequency of a stationary target that becomes progressively distant. Cardiorespiratory responses, blood lactate concentration, and perceived exertion were measured. A verification phase was also performed in both tests to confirm the maximal physiological outcomes. The graded karate test evoked similar maximal responses to the running protocol: V̇O₂ (57.4 ± 5.1 vs 58.3 ± 3.5 mL·kg^-1·min^-1; p = 0.53), heart rate (192 ± 6 vs 193 ± 10]beats.min^-1; p = 0.62) and blood lactate (14.6 ± 3.4 vs 13.1 ± 3.0 mmol·L^-1; p = 0.14) with a shorter duration (351 ± 71 vs 640 ± 9 s; p < 0.001). Additionally, the graded karate test evoked higher V̇O₂ (72.6 ± 6.5 vs 64.4 ± 4.3 %V̇O_2MAX; p = 0.005) and heart rate (89.4 ± 4.6 vs 77.3 ± 7.2 %HR_MAX p < 0.001) at the ventilatory threshold and a higher heart rate (97.0 ± 2.4 vs 92.9 ± 2.2 %HR_MAX; p = 0.02) at the respiratory compensation point. Incremental and verification phases evoked similar responses in V̇O₂ and minute-ventilation during both tests. This novel displacement-based sport-specific test evoked similar maximal and higher submaximal responses, indicating a superior pathway to assess karate athletes.Key points

• The displacement-based graded karate test (GKT) yielded similar maximal and higher submaximal physiological responses than the ‘gold-standard’ CPET.
• The graded karate test (GKT) provides a more ecologically valid approach to assess the cardiorespiratory conditioning of karate athletes.
• Manipulating the target distance presents itself as a novel strategy that allows for the development of cardiorespiratory fitness combined with the specific ability to sustain propelling power.

Key words: Oxygen uptake, ventilatory thresholds, heart rate, blood lactate, martial arts     

Cardiorespiratory Responses to Stationary Running in Water and on Land

The aim of the study was to compare maximal and submaximal cardiorespiratory responses between progressive tests on a treadmill on land (TRE), and stationary running on land (SRL) and in water (SRW), while also comparing two methods of determining the second turn point (ST) (ventilatory curve and heart rate deflection point). The study sample consisted of nine active women (23 ± 1.94 years) that performed three maximal protocols in separate days. Heart rate (HR) and oxygen uptake (VO₂) were measured in all sessions. The data were analyzed using repeated-measures ANOVA and two-way repeated measures ANOVA with post-hoc Bonferroni test. Greater values of maximal HR (HR_max) and HR at ST (HR_ST) were observed during exercise performed on TRE and during the SRL, compared to the SRW (p < 0.05). The results for maximal VO₂ (VO_2max) and VO₂ at ST (VO_2ST) showed greater and significant values on TRE compared to STL and STW (p < 0.05). Furthermore, the HR and VO₂ corresponding to the ST showed similar values between the two methods. Thus, the main conclusion of the present study was that the HR deflection point seems to be a simple and practical alternative method for determining the ST in all protocols analyzed.

Key Points

• The maximal and submaximal (second turn point) oxygen uptake were influenced by the type of exercise, as these responses were similar in both water-based and land-based stationary running protocols and different from those obtained during the treadmill running, that presented greater values compared with both stationary running protocols.
• The heart rate deflection point can be used for determining the second turn point during stationary running test in aquatic environment.
• Caution is necessary in the interpretation of the application of the heart rate deflection point in water aerobics exercises because we analyzed only young women performing one water-based exercise.

Key words: Ventilatory curve, deflection point, second turn point, heart rate, oxygen uptake, water-based exercise     

Using Session RPE to Monitor Different Methods of Resistance Exercise

The purpose of this study was to compare session rating of perceived exertion for different resistance training techniques in the squat exercise. These techniques included traditional resistance training, super slow, and maximal power training. Fourteen college-age women (Mean ± SD; age = 22 ± 3 years; height = 1.68 ± 0. 07 m) completed three experimental trials in a randomized crossover design. The traditional resistance training protocol consisted of 6 sets of 6 repetitions of squats using 80% of 1-RM. The super slow protocol consisted of 6 sets of 6 repetitions using 55% of 1-RM. The maximal power protocol consisted of 6 sets of 6 repetitions using 30% of 1-RM. Rating of perceived exertion (RPE) measures were obtained following each set using Borg’s CR-10 scale. In addition, a session RPE value was obtained 30 minutes following each exercise session. When comparing average RPE and session RPE, no significant difference was found. However, power training had significantly lower (p < 0.05) average and session RPE (4.50 ± 1.9 and 4.5 ± 2.1) compared to both super slow training (7.81 ± 1.75 and 7.43 ± 1.73) and traditional training (7.33 ± 1.52 and 7.13 ± 1.73). The results indicate that session RPE values are not significantly different from the more traditional methods of measuring RPE during exercise bouts. It does appear that the resistance training mode that is used results in differences in perceived exertion that does not relate directly to the loading that is used. Using session RPE provides practitioners with the same information about perceived exertion as the traditional RPE measures. Taking a single measure following a training session would appear to be much easier than using multiple measures of RPE throughout a resistance training workout. However, practitioners should also be aware that the RPE does not directly relate to the relative intensity used and appears to be dependent on the mode of resistance exercise that is used.

Key Points

• The present study showed that session RPE values are not significantly different from the more traditional methods of measuring RPE during exercise bouts.
• Power training had significantly lower average and session RPE compared to both super slow training and traditional training
• It does appear that the resistance training mode that is used results in differences in perceived exertion that does not relate directly to the loading that is used.

Key words: Weight lifting, non-traditional resistance training     

Physiologic Responses of Paraplegics and Quadriplegics to Passive and Active Leg Cycle Ergometry

ABSTRACT

The purposes of this study were three-fold: (a) to determine acute physiologic responses of spinal cord injured (SCI) subjects to peak levels of leg cycle ergometry utilizing functional neuromuscular stimulation (FNS) of paralyzed leg muscles, (b) to determine the relative contributions of passive and active components of FNS cycling to the peak physiologic responses, and (c) to compare these physiologic responses between persons who have quadriplegia and those who have paraplegia. Thirty SCI subjects (17 quadriplegics and 13 paraplegics) performed a discontinuous graded FNS exercise test from rest to fatigue on an ERGYS 1 ergometer. Steady-state physiologic responses were determined by open-circuit spirometry, impedance cardiography with ECG, and auscultation. In the combined statistics of both groups, it was noted that peak FNS cycling significantly increased (from rest levels) mean oxygen uptake by 255%, arteriovenous O₂ difference VO₂ and V_E, Q and a-vO₂and VCO by 69%, and Stroke Volume by 45%, While total peripheral vascular resistance decreased by 43%. Mean peak power output for paraplegics (15 W) was significantly higher than for quadriplegics (9 W), eliciting higher peak levels of pulmonary ventilation and sympathetically mediated hemodynamic responses such as cardiac output, heart rate, and systolic and diastolic arterial blood pressure. Passive cycling without FNS produced no statistically significant increases in physiologic responses above the resting level in either group. (J Am Paraplegia Soc 1990; 13: 33–39)     

Short-Term Bone Biochemical Response to a Single Bout of High-Impact Exercise

Bone response to a single bout of exercise can be observed with biochemical markers of bone formation and resorption. The purpose of this study was to examine the response of bone biochemical markers to a single bout of exhaustive high-impact exercise. 15 physically active young subjects volunteered to participate. The subjects performed continuous bilateral jumping with the ankle plantarflexors at 65 % of maximal ground reaction force (GRF) until exhaustion. Loading was characterized by analyzing the GRF recorded for the duration of the exercise. Venous blood samples were taken at baseline, immediately after, 2h and on day 1 and day 2 after the exercise. Procollagen type I amino terminal propeptide (P1NP, marker of bone formation) and carboxyterminal crosslinked telopeptide (CTx, marker of bone resorption) were analyzed from the blood samples. CTx increased significantly (32 %, p = 0.015) two days after the exercise and there was a tendensy towards increase seen in P1NP (p = 0.053) one day after the exercise. A significant positive correlation (r = 0.49 to 0.69, p ≤ 0.038) was observed between change in P1NP from baseline to day 1 and exercise variables (maximal slope of acceleration, body weight (BW) adjusted maximal GRF, BW adjusted GRF exercise intensity and osteogenic index). Based on the two biochemical bone turnover markers, it can be concluded that bone turnover is increased in response to a very strenuous single bout of exhaustive high-impact exercise.

Key points

• Studies on bone acute biochemical response to loading have yielded unequivocal results.
• There is a paucity of research on the biochemical bone response to high impact exercise.
• An increase in bone turnover was observed one to two days post exercise.

Key words: Bone biochemical marker, jumping, bone turnover, osteogenic index     

Effect of Preoperative Exercise on Cardiorespiratory Function and Recovery After Surgery: a Systematic Review

Background

This systematic review aims to investigate the extent to which preoperative conditioning (PREHAB) improves physiologic function and whether it correlates with improved recovery after major surgery.

Methods

An electronic database search identified randomized controlled trials (RCTs) investigating the safety and efficacy of PREHAB. The outcomes studied were changes in cardiorespiratory physiologic function, clinical outcomes (including length of hospital stay and rates of postoperative complications), and measures of changes in functional capacity (physical and psychological).

Results

Eight low- to medium-quality RCTs were included in the final analysis. The patients were elderly (mean age >60 years), and the exercise programs were significantly varied. Adherence to PREHAB was low. Only one study found that PREHAB led to significant improvement in physiologic function correlating with improved clinical outcomes.

Conclusion

There are only limited data to suggest that PREHAB confers any measured physiologic improvement with subsequent clinical benefit. Further data are required to investigate the efficacy and safety of PREHAB in younger patients and to identify interventions that may help improve adherence to PREHAB.     

Hemodynamic and Lactic Acid Responses to Proprioceptive Neuromuscular Facilitation Exercise

The hemodynamic and metabolic responses to proprioceptive neuromuscular facilitation (PNF) exercise were examined in 32 male university students (aged 19-28 years). Ten repetitions of PNF exercises were applied to the subjects’ dominant upper extremities in the following order: as an agonist pattern flexion, adduction and external rotation; and as an antagonist pattern extension, abduction and internal rotation. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), double product (DP), and blood lactate concentration (La) were determined before, immediately after, and at 1^st, 3^rd, and 5^th minutes after PNF exercise. A one-way ANOVA with repeated measures indicated significant differences in HR, SBP, DBP, DP and La immediately after PNF exercise. HR increased from 81 (±10) to 108 (±15) b·min^-1 (p < 0.01), SBP increased from 117 (±10) to 125 (±11) mmHg (p < 0.01), DBP increased from 71 (±10) to 75 (±8) mmHg (p < 0.01), DP increased from 96 (±16) to 135 (±24) (p < 0.01), and La increased from 0.69 (±0.31) to 3.99 (±14.63) mmol·L^-1 (p < 0.01). Thus PNF exercise resulted in increased hemodynamic responses and blood lactate concentration that indicate a high strain on the cardiovascular system and anaerobic metabolism in healthy subjects.

Key Points

• PNF exercises resulted in increased hemodynamic responses.
• Repeated PNF exercises resulted in an increased blood lactate concentration.

Key words: Heart rate, systolic blood pressure, diastolic blood pressure, double product, PNF     

Megasession: Excision of Numerous Skin Cancers in a Single Session

Background A large number of synchronous skin cancers in a patient may be managed with extensive removal in one session or limited removal in several sessions.
Objective Our objective was to prospectively evaluate the experiences of patients undergoing excisional surgery for multiple nonmelanoma skin cancers in one session.
Methods Patients scheduled for excision of five or more skin lesions in one operative session were prospectively surveyed and followed for outcomes. Patients were surveyed immediately postoperatively and 7 and 90 days postoperatively.
Results Ten patients were prospectively enrolled. They had a previous history of numerous skin cancers (median 76; range 4–551). The median number of lesions excised was 8 (range 5–21). All patients received local anesthesia, 90% received sedation, and none had general anesthesia. The median duration of the procedure was 480 minutes. Nine patients tolerated the procedure well. Two patients were electively hospitalized for observation because of the extent of surgery. Nine patients were very satisfied with the megasession.
Conclusion Carefully selected patients with extensive skin cancer can tolerate excisional surgery of a large number of cutaneous neoplasms in one session, with few and readily managed complications. Most of our patients preferred extensive tumor removal in one session to removal of fewer tumors in several sessions.     

Physiologic Responses of Elite Paraplegic Road Racers to Prolonged Exercise

ABSTRACT

The purpose of this study was to determine cardiopulmonary and selected metabolic responses in spinal cord injured (SCI) paraplegics during prolonged arm crank exercise (ACE). Six male and one female elite SCI paraplegic (T4-12 lesions) road racers performed 40 continuous minutes of ACE at 60% of peak ACE oxygen uptake (VO₂). Blood samples (30 ml) were collected via antecubital venipuncture at rest and minutes 20 and 40 of ACE for determinations of hemoglobin, hematocrit, serum free fatty acid (FFA), and blood lactate (LA) concentrations. No significant differences were observed over time for V0₂ or pulmonary ventilation. Heart rate recorded at minutes 30 and 40 was significantly elevated’ above HR at minutes 10 and 20 of ACE indicating the presence of an upward drift in HR in paraplegics performing prolonged ACE. Compared to rest, LA concentration was significantly higher at minute 20 and remained relatively stable thereafter. A significant increase in FFA concentration at minute 40 combined with a significant decline in the respiratory exchange ratio suggested a preference for lipid substrate utilization by exercising muscle as ACE continued. The data indicate that the autonomic sympathetic nervous system impairment associated with paraplegia had no apparent adverse effects on cardiopulmonary or metabolic adjustments to prolonged ACE in these well-trained subjects.     

Caffeine Attenuates Acute Growth Hormone Response to a Single Bout of Resistance Exercise

The purpose of this study was to investigate the effects of caffeine consume on substrate metabolism and acute hormonal responses to a single bout of resistance exercise (RE). Ten resistance-trained men participated in this study. All subjects performed one repetition maximum (1RM) test and then performed two protocols: caffeine (CAF, 6 mg·kg^-1) and control (CON) in counter balanced order. Subjects performed RE (8 exercises, 3 sets of 10 repetitions at 75% of 1RM) after caffeine or placebo ingestion one hour prior to RE. Blood samples collected prior to treatment ingestion (pre-60), immediately prior to RE (pre-exe), and 0, 15, 30 min post to RE (P0, P15, P30) for analysis of insulin, testosterone, cortisol, growth hormone, glucose, free fatty acid and lactic acid. Each experiment was separated by seven days. In this study, statistical analysis of a two-way analysis of variance (treatment by time) with repeated measures was applied. After ingesting caffeine, the concentrations of free fatty acid (pre- exe, P0, P15, P30) in CAF were significantly higher than CON (p < 0.05). Additionally, the responses of GH (P0, P15, P30) in CAF were significantly lower than CON (p < 0.05), whereas the concentrations of insulin, testosterone and cortisol were not different between CAF and CON (p < 0.05) after RE. The results of this study indicated that caffeine ingestion prior to RE might attenuate the response of GH. This effect might be caused by the elevation in blood FFA concentration at the beginning of RE.

Key points

• Caffeine ingestion may attenuate the response of GH to a single bout of resistance exercise.
• The depression of GH response may be caused by the elevation in serum FFA concentration at the beginning of resistance exercise.
• Caffeine ingestion before resistance exercise may not alert the concentration of cortisol and testosterone.

Key words: Nutritional supplementation, growth hormone, free fatty acid, ergogenic aids     

Arm vs. Combined Leg and Arm Exercise: Blood Pressure Responses and Ratings of Perceived Exertion at the Same Indirectly Determined Heart Rate

Pre-participation screening is very important for prescribing and practising exercise safely. The aim of this study was to investigate both ratings of perceived exertion (RPE) and blood pressure responses in two different types of exercises with matching duration and indirectly determined working heart rate (HR). Participants were 23 male students, who were generally healthy but sedentary. The time course of their RPE and blood pressure during a 50- minute work-out session on an arm crank ergometer and a cross trainer were compared. RM-ANOVA showed both a higher RPE (p < 0.001) and diastolic blood pressure (DBP) (p < 0.001) response to the arm exercise that were shown significantly correlated (r = 0.883; p = 0.008). Linear regression analysis (p = 0.001) confirmed the ability to predict the time course of DBP by knowing the RPE on the arm crank ergometer. Even if people use the recommended relative intensity, the HR method is not always safe for health without pre-participation screening because exercise characteristics can negatively influence physiological responses. The HR method could be substituted by the RPE method.

Key points

• Arm Crank Ergometer elicits a higher diastolic blood pressure response respect to Cross Trainer when people exercise at the same heart rate.
• Arm Crank Ergometer elicits a higher ratings of perceived exertion respect to Cross trainer when people exercise at the same heart rate.
• Indirect determined working heart rate is not always safe even if the theoretical intensity is that recommended for health.
• Rating of perceived exertion method should be used instead of heart rate method to avoid the dangerous physiological responses observed.

Key words: Diastolic blood pressure, arm crank ergometer, cross trainer     

Effect of Different Rest Intervals,Between Sets,on Muscle Performance During Leg Press Exercise,in Trained Older Women

The purpose of this study was to assess the effect of different rest intervals (RI) between sets on number of repetitions, sustainability of repetitions, and total volume during a leg press exercise. Seventeen resistance-trained older women (68.0 ± 5.9 years, 71. 2 ± 11.7 kg, 1.58 ± 0.07 m) participated in the study. All participants performed three sets to voluntary exhaustion, with loads that corresponded to 15 maximum repetitions, in two experimental sessions (that ranged from 48 to 72 hours apart). In each session, one of two RI (one-minute: RI-1 and three minute: RI-3) was tested, employing a randomized and counterbalanced design. For both RI, significant reductions (p < 0.05) were observed in the number of repetitions and sustainability of repetitions, from the first to the second and third sets. Differences (p < 0.05) between the RI also were observed in the two final sets. The total volume for the RI-3 session was statistically higher (29.4%, p < 0.05) as compared to the RI-1 session. The length of the RI between sets influenced the number of repetitions, sustainability of repetitions, and total volume. The longer RI should be used, therefore, when the goal of training is to increase the total volume.

Key points

• This study examined the influence of rest intervals, between sets, on muscle performance during leg press exercise, in trained older women.
• When multiple sets were performed to voluntary exhaustion, neither short and long rest interval (1 and 3 minutes, respectively) promoted the sustainability of repetitions in subsequent sets.
• A longer rest interval seems to be necessary for a higher number of repetitions in subsequent sets, and with increase in time of tension and total volume.

Key words: Aging, muscle fatigue, muscle endurance, recovery.     

Acute Bone Marker Responses to Whole-Body Vibration and Resistance Exercise in Young Women

Whole-body vibration (WBV) augments the musculoskeletal effects of resistance exercise (RE). However, its acute effects on bone turnover markers (BTM) have not been determined. This study examined BTM responses to acute high-intensity RE and high-intensity RE with WBV (WBV + RE) in young women (n = 10) taking oral contraceptives in a randomized, crossover repeated measures design. WBV + RE exposed subjects to 5 one-minute bouts of vibration (20 Hz, 3.38 peak-peak displacement, separated by 1 min of rest) before RE. Fasting blood samples were obtained before (Pre), immediately after WBV (PostVib), immediately after RE (IP), and 30-min after RE (P30). Bone alkaline phosphatase did not change at any time point. Tartrate-resistant acid phosphatase 5b significantly increased (p < 0.05) from the Pre to PostVib, then decreased from IP to P30 for both conditions. C-terminal telopeptide of type I collagen (CTX) significantly decreased (p < 0.05) from Pre to PostVib and from Pre to P30 only for WBV + RE. WBV + RE showed a greater decrease in CTX than RE (?12.6% ± 4.7% vs ?1.13% ± 3.5%). In conclusion, WBV was associated with acute decreases in CTX levels not elicited with RE alone in young women.     

Single Session Effects of Treatment Components Within a Specialized Inpatient Posttraumatic Stress Disorder Program

This study examined the potential contributions of individual treatment components within one inpatient posttraumatic stress disorders (PTSD) program. Fifteen treatment components were assessed by a self-report instrument administered to a cohort of veterans just before and immediately after each session approximately halfway through the program. Components with an external focus, action modality, and, secondarily, little Vietnam content were associated with more improvement than components with an internal focus, verbal modality, or high Vietnam content. Improvement was greatest in veterans with fewer PTSD symptoms. Short-term improvement was not correlated with veterans' ratings at discharge of component effectiveness. These results were later confirmed on a second cohort. This study supports the potential roles of distraction and physical release, as opposed to exploratory verbal discussion, in the treatment of chronic combat-related PTSD.     

Effects of a Single Bout of Interval Hypoxia on Cardiorespiratory Control in Patients With Type 1 Diabetes

Hypoxemia is common in diabetes, and reflex responses to hypoxia are blunted. These abnormalities could lead to cardiovascular/renal complications. Interval hypoxia (IH) (5–6 short periods of hypoxia each day over 1–3 weeks) was successfully used to improve the adaptation to hypoxia in patients with chronic obstructive pulmonary disease. We tested whether IH over 1 day could initiate a long-lasting response potentially leading to better adaptation to hypoxia. In 15 patients with type 1 diabetes, we measured hypoxic and hypercapnic ventilatory responses (HCVRs), ventilatory recruitment threshold (VRT-CO₂), baroreflex sensitivity (BRS), blood pressure, and blood lactate before and after 0, 3, and 6 h of a 1-h single bout of IH. All measurements were repeated on a placebo day (single-blind protocol, randomized sequence). After IH (immediately and after 3 h), hypoxic and HCVR increased, whereas the VRT-CO₂ dropped. No such changes were observed on the placebo day. Systolic and diastolic blood pressure increased, whereas blood lactate decreased after IH. Despite exposure to hypoxia, BRS remained unchanged. Repeated exposures to hypoxia over 1 day induced an initial adaptation to hypoxia, with improvement in respiratory reflexes. Prolonging the exposure to IH (>2 weeks) in type 1 diabetic patients will be a matter for further studies.Diabetes is closely related to impaired function of the autonomic nervous system (ANS). As a consequence, autonomic dysfunction can worsen the prognosis of the disease and result in serious complications (1,2).Assuming that ANS abnormalities such as sympathetic overactivity or reduced cardiorespiratory reflexes might at an early stage be attributed to a functional origin (as they can be favorably influenced by simple functional maneuvers) rather than organic lesions (3), they could possibly be reversible by an appropriate intervention. In diabetic patients, low oxygen content (hypoxemia) is common in most organ and tissues (4–8). Hypoxia in the blood or tissues is known to induce sympathetic activation, hence, altering cardiovascular reflex tests regardless of neural damage (9,10).Interval hypoxia (IH) could be a useful strategy to improve hypoxia, since IH has largely been implemented in the adaptation to high altitude (11,12). Due to the improved adaptation to hypoxia, IH also improves exercise performance in athletes (13) and improves ANS function in various diseases (14,15). IH consists of repeated short periods of hypoxia (5–6 min) interspersed by equal periods of normoxia, thus creating a sort of stress that in turn evokes a counterregulatory response by altering the preexisting homeostasis. If adequately administered, sufficient repetitions lead to a persisting supercompensatory (“training”) effect (16,17) and improved response to hypoxia. The use of IH in patients with chronic bronchitis (18) increased ventilation, oxygen saturation, and chemoreflex activity; reduced hypoxia-dependent sympathetic overactivity; and right shifted the lactate-load curve during exercise as an effect of improved aerobic metabolism (19). IH also modifies the number of circulating immune cells, due to the links between ANS, immune system, and hypoxia (20).In patients with diabetes, abnormal activity of respiratory reflexes (21–26) and reduced responses to hypoxia are frequently observed (27,28), and the immune defense is depressed (29). Altogether, these considerations suggest that IH could induce favorable results in diabetes.However, as IH has never been applied in patients with type 1 diabetes before, we tested whether a single short bout of IH could elicit favorable changes that improve the hypoxia and the respiratory reflexes and could lead to improved ANS function. In addition, since the responses to hypoxia are multidimensional, we tested its initial effects on the immune system and on the aerobic/anaerobic metabolism at rest by monitoring the lactate production after IH. Finally, we assessed the possible effects of IH on lipid peroxidation and formation of malondialdehyde (MDA), which are markers for cell damage and oxidative stress, respectively, and are generally used when the effects of hypoxia interventions are to be evaluated (30).The aim of this study was to examine the chain of events occurring after one single bout of IH in patients with type 1 diabetes. For this purpose, we examined cardiorespiratory, metabolic, and hematological responses before and at different times after 1 h of IH and followed the changes over the rest of the same day (6 h).     

Effect of Immediate and Delayed Cold Water Immersion After a High Intensity Exercise Session on Subsequent Run Performance

The purpose of the study was to determine the effects of cold water immersion (CWI) performed immediately or 3 h after a high intensity interval exercise session (HIIS) on next-day exercise performance. Eight male athletes performed three HIIS at 90%VO₂max velocity followed by either a passive recovery (CON), CWI performed immediately post-exercise (CWI(0)) or CWI performed 3 h post-exercise (CWI(3)). Recovery trials were performed in a counter balanced manner. Participants then returned 24 h later and completed a muscle soreness and a totally quality recovery perception (TQRP) questionnaire, which was then followed by the Yoyo Intermittent Recovery Test [level 1] (YRT). Venous blood samples were collected pre-HIIS and pre-YRT to determine C-Reactive Protein (CRP) levels. Significantly more shuttles were performed during the YRT following CWI(0) compared to the CON trial (p=0.017, ES = 0. 8), while differences between the CWI(3) and the CON trials approached significance (p = 0.058, ES = 0.5). Performance on the YRT between the CWI(0) and CWI(3) trials were similar (p = 0.147, ES = 0. 3). Qualitative analyses demonstrated a 98% and 92% likely beneficial effect of CWI(0) and CWI(3) on next day performance, compared to CON, respectively, while CWI(0) resulted in a 79% likely benefit when compared to CWI(3). CRP values were significantly lower pre-YRT, compared to baseline, following CWI(0) (p = 0.0.36) and CWI(3) (p = 0.045), but were similar for CON (p = 0.157). Muscle soreness scores were similar between trials (p = 1.10), while TQRP scores were significantly lower for CON compared to CWI(0) (p = 0.002 ) and CWI(3) (p = 0.024). Immediate CWI resulted in superior next-day YRT performance compared to CON, while delayed (3 h) CWI was also likely to be beneficial. Qualitative analyses suggested that CWI(0) resulted in better performance than CWI(3). These results are important for athletes who do not have immediate access to CWI following exercise.

Key points

• Performance of cold water immersion as a recovery procedure following exercise is better than performing no recovery procedure
• Athletes, coaches and sport trainers should implement cold water immersion post-exercise irrespective of the time of administration.
• Where possible, cold water immersion should be performed immediately post-exercise to gain maximal recovery benefits.

Key words: Recovery, cold water immersion, C-Reactive Protein, yoyo test     

Reliability of Kinematics and Kinetics Associated with Horizontal Single Leg Drop Jump Assessment. a Brief Report.

Determining the reliability of a unilateral horizontal drop jump for displacement provided the focus for this research. Eighteen male subjects were required to step off a 20cm box and land on a force plate with one leg and thereafter jump for maximal horizontal displacement on two different days. Dependent variables from the jump assessment included mean and peak vertical (V) and horizontal (H) ground reaction forces (GRF) and impulses, horizontal displacement and contact time. The between-trial variability of all kinematic and kinetic measures was less than 7%. The most consistent measure over both trials was the horizontal displacement jumped (1.2 to 1.4%) and the most variable were the contact time the first day (6.5%) and peak HGRF the second day (4.3%). In all cases there was less variation associated with the second rather than the first day. In terms of test-retest variability the percent changes in the means and coefficient of variations (CVs) were all under 10%. The smallest changes in the mean (0.43 %), least variation (< 2.26 %) and second highest intraclass correlation co-efficient (ICC = 0.95) were found for horizontal displacement jumped. The highest ICC (0.96) was found for horizontal impulse. Given the reliability of the single leg drop jump, it may offer better prognostic and diagnostic information than that obtained with bilateral vertical jumps.

Key points

• There is a need for greater understanding and utilisation of assessment techniques that assess both the horizontal and vertical components of force/power production.
• The single leg drop jump is an assessment that exhibits high face validity (a unilateral jump involving both vertical and horizontal propulsive forces that also involves pre-load) but reliability needed to be quantified.
• The reliability of the many kinematic and kinetic variables quantified in this study were similar to those published in research in this area and future research needs to determine the clinical and practical significance of this test.

Key words: Ground reaction force, impulse, assessment