Effects of active, passive or no warm-up on metabolism and performance during high-intensity exercise

Revisiting the 'Whys' and 'Hows' of the Warm-Up: Are We Asking the Right Questions?

The warm-up is considered beneficial for increasing body temperature, stimulating the neuromuscular system and overall preparing the athletes for the demands of training sessions and competitions. Even when warm-up-derived benefits are slight and transient, they may still benefit preparedness for subsequent efforts. However, sports training and competition performance are highly affected by contextual factors (e.g., how is the opponent acting?), and it is not always clear what should be the preferred warm-up modalities, structure and load for each athlete and context. Further, we propose that the warm-up can also be used as a pedagogical and training moment. The warm-up may serve several different (albeit complementary) goals (e.g., rising body temperature, neuromuscular activation, attentional focus) and be performed under a plethora of different structures, modalities, and loads. The current commentary highlights the warm-up period as an opportunity to teach or improve certain skills or physical capacities, and not only as a preparation for the subsequent efforts. Moreover, the (justified) call for individualized warm-ups would benefit from educating athletes about exploring different warm-up tasks and loads, providing a broad foundation for future individualization of the warm-up and for more active, engaged, and well-informed participation of the athletes in deciding their own warm-up practices.

3-Week passive acclimation to extreme environmental heat (100± 3 °C) in dry sauna increases physical and physiological performance among young semi-professional football players

This manuscript aims to evaluate the influence of a novel passive heat acclimation program among human participants in the physical performance, as well as in several physiological parameters. 36 male football players were acclimated using a dry sauna bath to extreme hot (100 ± 3 °C), performing a total of nine sauna sessions with a weekly frequency of three sessions. The players were randomly into the sauna group (SG; n = 18; age: 20.69 ± 2.09 years) and the control group (CG; n = 18; age: 20.23 ± 1.98 years). All participants performed maximal effort test until exhaustion as well as hamstring flexibility test before and after the acclimation program. Anthropometric, respiratory, circulatory, hematological and physiological variables were evaluated at the beginning and at the end of the survey. Statistical analysis consisted of a Mann-Whitney U test to determine differences between groups at the beginning and at the end of the survey and a Wilcoxon test for paired samples to compare the differences for each group separately. Additionally, size effects of the pre-post acclimation changes were calculated. After the acclimation program SG participants experienced a diminution in body weight (p < 0.01), body mass index (p < 0.01), body fat (p < 0.05) and fat percentage (p < 0.05) decreased. Hamstring flexibility (p < 0.05) and work capacity (p < 0.05) increased. External basal temperature decreased (p < 0.05) as well as post-exercise systolic and diastolic blood pressures (p < 0.05). Finally, maximal oxygen uptake (ml Kg^-1 min^-1) (p < 0.05), maximal minute ventilation (p < 0.05) and maximal breath frequency (p < 0.05) increased at the end of the intervention. There were no significant changes in the CG in any variable. Favorable adaptations have been observed in this survey, suggesting a beneficial effect of extreme heat acclimation on physical performance. Several of the observed responses seem interesting for sport performance and health promotion as well. However, this is a novel, extreme protocol which requires further research.

The Effect of Lower Body Anaerobic Pre-Loading on Upper Body Ergometer Time Trial Performance

Pre-competitive conditioning has become a substantial part of successful performance. In addition to temperature changes, a metabolic conditioning can have a significant effect on the outcome, although the right dosage of such a method remains unclear. The main goal of the investigation was to measure how a lower body high-intensity anaerobic cycling pre-load exercise (HIE) of 25 s affects cardiorespiratory and metabolic responses in subsequent upper body performance. Thirteen well-trained college-level male cross-country skiers (18.1 ± 2.9 years; 70.8 ± 7.6 kg; 180.6 ± 4.7 cm; 15.5 ± 3.5% body fat) participated in the study. The athletes performed a 1000-m maximal double-poling upper body ergometer time trial performance test (TT) twice. One TT was preceded by a conventional low intensity warm-up (TT_low) while additional HIE cycling was performed 9 min before the other TT (TT_high). Maximal double-poling performance after the TT_low (225.1 ± 17.6 s) was similar (p > 0.05) to the TT_high (226.1 ± 15.7 s). Net blood lactate (La) increase (delta from end of TT minus start) from the start to the end of the TT_low was 10.5 ± 2.2 mmol L⁻¹ and 6.5 ± 3.4 mmol L⁻¹ in TT_high (p < 0.05). La net changes during recovery were similar for both protocols, remaining 13.5% higher in TT_high group even 6 min after the maximal test. VCO₂ was lower (p < 0.05) during the last 400-m split in TT_high, however during the other splits no differences were found (p < 0.05). Respiratory exchange ratio (RER) was significantly lower in TT_high in the third, fourth and the fifth 200 m split. Participants individual pacing strategies showed high relation (p < 0.05) between slower start and faster performance. In conclusion, anaerobic metabolic pre-conditioning leg exercise significantly reduced net-La increase, but all-out upper body performance was similar in both conditions. The pre-conditioning method may have some potential but needs to be combined with a pacing strategy different from the usual warm-up procedure.

The effect of cold ambient temperature and preceding active warm-up on lactate kinetics in female cyclists and triathletes

The aim of this study was to evaluate the effect of cold ambient temperature on lactate kinetics with and without a preceding warm-up in female cyclists/triathletes. Seven female cyclists/triathletes participated in this study. The randomized, crossover study included 3 experimental visits that comprised the following conditions: (i) thermoneutral temperature (20 °C; NEU); (ii) cold temperature (0 °C) with no active warm-up (CNWU); and (iii) cold temperature (0 °C) with 25-min active warm-up (CWU). During each condition, participants performed a lactate threshold (LT) test followed by a time to exhaustion trial at 120% of the participant's peak power output (PPO) as determined during prior peak oxygen consumption testing. Power output at LT with CNWU was 10.2% ± 2.6% greater than with NEU, and the effect was considered very likely small (effect size (ES) = 0.59, 95%-99% likelihood). Power output at LT with CNWU was 4.2% ± 5.4% greater than with CWU; however, the effect was likely trivial (ES = 0.25, 75%-95% likelihood). At LT, there were no significant differences between interventions groups in oxygen consumption, blood lactate concentration, heart rate, or rating of perceived exertion. Time to exhaustion at 120% at PPO was 11% longer with CNWU than with CWU (ES = 0.62, respectively), and this effect was likely small. These findings suggest that power output at LT was higher in CNWU compared with NEU. Additionally, time to exhaustion at 120% of PPO was higher in CNWU compared with CWU and no different than NEU; these differences likely result in a small improvement in performance with CNWU versus CWU and NEU.

Quantifying the Physical Response to a Contemporary Amateur Boxing Simulation

Finlay, MJ, Greig, M, and Page, RM. Quantifying the physical response to a contemporary amateur boxing simulation. J Strength Cond Res 32(4): 1005-1012, 2018-This study examined the physical response to a contemporary boxing-specific exercise protocol (BSEP), based on notational analysis of amateur boxing. Nine male senior elite amateur boxers completed a 3 × 3-minute BSEP, with a 1-minute passive recovery period interspersing each round. Average (HRave) and peak (HRpeak) heart rates, average (V[Combining Dot Above]O2ave) and peak oxygen consumptions (V[Combining Dot Above]O2peak), blood lactate (BLa) concentrations, rating of perceived exertion, and both triaxial and uniaxial PlayerLoad metrics were recorded during the completion of the BSEP. Blood lactate concentration increased significantly in each round (Round 1 = 2.4 ± 1.3 mmol·L; Round 2 = 3.3 ± 1.7 mmol·L; Round 3 = 4.3 ± 2.6 mmol·L). Significantly lower HRave and HRpeak values were found in the first round (HRave: 150 ± 15 b·min; HRpeak: 162 ± 12 b·min) when compared with the second (HRave: 156 ± 16 b·min; HRpeak: 166 ± 13 b·min) and third (HRave: 150 ± 15 b·min; HRpeak: 169 ± 14 b·min). No significant differences were found in any of the V[Combining Dot Above]O2 or PlayerLoad metrics recorded during the BSEP. The BSEP based on notational analysis elicited a fatigue response across rounds, confirming its validity. The BSEP can be used as a training tool for boxing-specific conditioning with implications for reduced injury risk, and to assess the physical response to boxing-specific interventions. Moreover, the BSEP can also be manipulated to suit all levels of participants or training phases, with practical applications in performance monitoring and microcycle periodization.

Performance Enhancing Effect of Metabolic Pre-conditioning on Upper-Body Strength-Endurance Exercise

High systemic blood lactate (La) was shown to inhibit glycolysis and to increase oxidative metabolism in subsequent anaerobic exercise. Aim of this study was to examine the effect of a metabolic pre-conditioning (MPC) on net La increase and performance in subsequent pull-up exercise (PU). Nine trained students (age: 25.1 ± 1.9 years; BMI: 21.7 ± 1.4) performed PU on a horizontal bar with legs placed on a box (angular hanging) either without or with MPC in a randomized order. MPC was a 26.6 ± 2 s all out shuttle run. Each trial started with a 15-min warm-up phase. Time between MPC and PU was 8 min. Heart rate (HR) and gas exchange measures (VO₂, VCO₂, and VE) were monitored, La and glucose were measured at specific time points. Gas exchange measures were compared by area under the curve (AUC). In PU without MPC, La increased from 1.24 ± 0.4 to 6.4 ± 1.4 mmol⋅l^-1, whereas with MPC, PU started at 9.28 ± 1.98 mmol⋅l^-1 La which increased to 10.89 ± 2.13 mmol⋅l^-1. With MPC, net La accumulation was significantly reduced by 75.5% but performance was significantly increased by 1 rep (4%). Likewise, net oxygen uptake VO₂ (50% AUC), pulmonary ventilation (VE) (34% AUC), and carbon dioxide VCO₂ production (26% AUC) were significantly increased during PU but respiratory exchange ratio (RER) was significantly blunted during work and recovery. MPC inhibited glycolysis and increased oxidative metabolism and performance in subsequent anaerobic upper-body strength-endurance exercise.

Cardiorespiratory fitness and aerobic performance adaptations to a 4-week sprint interval training in young healthy untrained females

Purpose

The aim of this study was to test the effects of sprint interval training (SIT) on cardiorespiratory fitness and aerobic performance measures in young females.

Methods

Eight healthy, untrained females (age 21 ± 1 years; height 165 ± 5 cm; body mass 63 ± 6 kg) completed cycling peak oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \dot{V}{\text{O}}_{2} $$\end{document}V˙O2 peak), 10-km cycling time trial (TT) and critical power (CP) tests pre- and post-SIT. SIT protocol included 4 × 30-s “all-out” cycling efforts against 7 % body mass interspersed with 4 min of active recovery performed twice per week for 4 weeks (eight sessions in total).

Results

There was no significant difference in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \dot{V}{\text{O}}_{2} $$\end{document}V˙O2 peak following SIT compared to the control period (control period: 31.7 ± 3.0 ml kg⁻¹ min⁻¹; post-SIT: 30.9 ± 4.5 ml kg⁻¹ min⁻¹; p > 0.05), but SIT significantly improved time to exhaustion (TTE) (control period: 710 ± 101 s; post-SIT: 798 ± 127 s; p = 0.00), 10-km cycling TT (control period: 1055 ± 129 s; post-SIT: 997 ± 110 s; p = 0.004) and CP (control period: 1.8 ± 0.3 W kg⁻¹; post-SIT: 2.3 ± 0.6 W kg⁻¹; p = 0.01).

Conclusions

These results demonstrate that young untrained females are responsive to SIT as measured by TTE, 10-km cycling TT and CP tests. However, eight sessions of SIT over 4 weeks are not enough to provide sufficient training stimulus to increase \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \dot{V}{\text{O}}_{2} $$\end{document}V˙O2 peak.

Warm-Up Strategies for Sport and Exercise: Mechanisms and Applications

It is widely accepted that warming-up prior to exercise is vital for the attainment of optimum performance. Both passive and active warm-up can evoke temperature, metabolic, neural and psychology-related effects, including increased anaerobic metabolism, elevated oxygen uptake kinetics and post-activation potentiation. Passive warm-up can increase body temperature without depleting energy substrate stores, as occurs during the physical activity associated with active warm-up. While the use of passive warm-up alone is not commonplace, the idea of utilizing passive warming techniques to maintain elevated core and muscle temperature throughout the transition phase (the period between completion of the warm-up and the start of the event) is gaining in popularity. Active warm-up induces greater metabolic changes, leading to increased preparedness for a subsequent exercise task. Until recently, only modest scientific evidence was available supporting the effectiveness of pre-competition warm-ups, with early studies often containing relatively few participants and focusing mostly on physiological rather than performance-related changes. External issues faced by athletes pre-competition, including access to equipment and the length of the transition/marshalling phase, have also frequently been overlooked. Consequently, warm-up strategies have continued to develop largely on a trial-and-error basis, utilizing coach and athlete experiences rather than scientific evidence. However, over the past decade or so, new research has emerged, providing greater insight into how and why warm-up influences subsequent performance. This review identifies potential physiological mechanisms underpinning warm-ups and how they can affect subsequent exercise performance, and provides recommendations for warm-up strategy design for specific individual and team sports.

Prophylactic Effects of Sauna on Delayed-Onset Muscle Soreness of the Wrist Extensors

BACKGROUND

High-intensity of exercise or unaccustomed eccentric exercise can cause the phenomenon of Exercise-Induced Muscle Damage (EIMD) which usually results in cramps, muscle strain, impaired muscle function and delayed-onset muscle soreness.

OBJECTIVES

This study investigated the prophylactic effects of sauna towards the symptoms associated with muscle damage from eccentric exercises of wrist extensor muscle group.

PATIENTS AND METHODS

A total of twenty-eight subjects (mean age 20.9 years old, SD = 1.6) were randomly divided into the sauna group (n = 14) and the control group (n = 14). In the sauna group, subjects received sauna before eccentric exercise of the wrist extensor. The eccentric exercises were conducted on the non-dominant arm by using an isokinetic dynamometer. Pain Intensity (PI), Pressure Pain Threshold (PPT) and passive range of motion of wrist flexion (PF-ROM) and extension (PE-ROM) were measured as pain variables. Grip Strength (GS) and Wrist Extension Strength (WES) were measured as variables of wrist extensor muscle function. All the measurements were performed at baseline, immediately after and from 1st to 8th days after the exercise-induced muscle damage.

RESULTS

The sauna group significantly demonstrated a lower deficit in ROM (passive flexion and passive extension), GS and WES following exercise than that of the control group (P < 0.05).

CONCLUSIONS

Sauna application prior to the exercise-induced muscle damage demonstrated effectiveness in reduction of sensory impairment (PF-ROM and PE-ROM) and improvement of muscle functions (GS, and WES) in wrist extensor muscle group.

The effect of a short practical warm-up protocol on repeated sprint performance

The aim of our study was to investigate the effect of a short, practical, 2-phase warm-up on repeated sprint performance when compared with more traditional warm-up protocols that contain stretching activities. Eleven subelite male soccer players completed a warm-up protocol that commenced with 5 minutes jogging at approximately 65% of maximal heart rate, followed by no stretching, static stretching, or dynamic stretching and finishing with a task-specific high-intensity activity. Using a crossover design, the 3 warm-up protocols were performed in a counterbalanced order with at least 48 hours between sessions. Repeated sprint performance was measured using a repeated sprint test that consisted of 6 × 40-m maximal sprints interspersed with a 20-second recovery. There were trivial differences in mean sprint time (0.2%) and posttest blood lactate (3.1%) between the 2-phase warm-up and the 3-phase warm-up that included dynamic stretching, whereas the short warm-up had a possibly detrimental effect on fastest sprint time (0.7%). Fastest (-1.1%) and mean (-1.2%) sprint times were quicker and posttest blood lactates were higher (13.2%) after the 2-phase warm-up when compared with the 3-phase warm-up that included static stretching. Although it is not harmful to complete a traditional 3-phase warm-up that includes dynamic stretching, it appears practical for athletes preparing for activities dependent on repeated sprint ability to complete a 2-phase warm-up consisting of a cardiovascular and specific high-intensity activity.

The effects of elapsed time after warm-up on subsequent exercise performance in a cold environment

Athletes often compete in cold environments and may face delays because of weather or race logistics between performance of a warm-up and the start of the race. This study sought to determine, (a) whether a delay after warm-up affects subsequent time trial (TT) performance and (b) if exposure to a cold environment has an additive effect. We hypothesized that after a warm-up, 30 minutes of rest in a cold environment would negatively affect subsequent rowing and running performance. In a temperate (temp; 24° C) or cold (cold; 5° C) environment, 5 rowers (33 ± 10 years; 83 ± 12 kg) and 5 runners (23 ± 2 years; 65 ± 8 kg) performed a 15-minute standardized warm-up followed by a 5- or 30-minute rest and then performed a 2-km rowing or 2.4 km running TT. The 5-minute rest following warm-up in the temperate environment (5Temp) served as the control trial to which the other experimental trials (5Cold; 30Temp; and 30Cold) were compared. Heart rate, lactate, and esophageal (Tes) and skin (Tsk) temperatures were measured throughout. Postrest and post-TT, Tes, and Tsk were lowest in the 30Cold trials. The greatest decrement in TT performance vs. 5Temp occurred in 30Cold (-4.0%; difference of 20 seconds). This difference is considered to have practical importance, as it was greater than the reported day-to-day variation for events of this type. We conclude that longer elapsed time following warm-up, combined with cold air exposure, results in potentially important reductions in exercise performance. Athletes should consider the appropriate timing of warm-up. In addition, performance may be preserved by maintaining skin and core temperatures following a warm-up, via clothing or other means.

Warm-up strategies of professional soccer players: practitioners' perspectives

Recent research has challenged the typical pre-match and half-time (HT) interval warm-up (WU) routines currently used by professional soccer players. This study surveyed 2010/11 season WU strategies and their underpinning scientific reasoning and situational factors via an internet-based questionnaire, which was distributed to English Premier League and Championship practitioners, of which 43% responded. The pre-match WU duration was 30.8 (8.2) min, ranging between 15-45 min, and 89% of practitioners administered a WU of ≥ 25 min. Respondents also reported a 12.4 (3.8) min period between the end of the WU and match kick-off. Eighty-nine per cent recognised the physiological benefits of re-WUs during this "down-time" period, with 63% instructing players to engage in such activity. During HT, 58% instructed players to re-WU either on the pitch or within stadia facilities, but "unwillingness of the coach/manager" (42%) and a "lack of time" (63%) were major constraints. Practitioners reported that 2.6 (1.6) min might be available for HT re-WUs. Factors such as match regulations, league policy, and stadia facilities were not generally considered as major barriers to the delivery of WUand re-WU strategies. We suggest that researchers consider the time-demands and barriers faced by practitioners whendeveloping experimental designs to examine WU regimens.

Effect of Warm-Up and Precooling on Pacing During a 15-km Cycling Time Trial in the Heat

Purpose:

The best way to apply precooling for endurance exercise in the heat is still unclear. The authors analyzed the effect of different preparation regimens on pacing during a 15-km cycling time trial in the heat.

Methods:

Ten male subjects completed four 15-km time trials (30°C), preceded by different preparation regimes: 10 min cycling (WARM-UP), 30 min scalp cooling of which 10 min was cycling (SC+WARM-UP), ice-slurry ingestion (ICE), and ice slurry ingestion + 30 min scalp cooling (SC+ICE).

Results:

No differences were observed in finish time and mean power output, although power output was lower for WARM-UP than for SC+ICE during km 13–14 (17 ± 16 and 19 ± 14 W, respectively) and for ICE during km 13 (16 ± 16 W). Rectal temperature at the start of the time trial was lower for both ICE conditions (~36.7°C) than both WARMUP conditions (~37.1°C) and remained lower during the first part of the trial. Skin temperature and thermal sensation were lower at the start for SC+ICE.

Conclusions:

The preparation regimen providing the lowest body-heat content and sensation of coolness at the start (SC+ICE) was most beneficial for pacing during the latter stages of the time trial, although overall performance did not differ.

Re-examination of the post half-time reduction in soccer work-rate

OBJECTIVES

To re-examine the work-rate of soccer players immediately after a passive half-time interval with an alternative approach to data reduction and statistical contrasts.

DESIGN

Time-motion analysis data (5Hz global positioning system), were collected from 20 elite youth players (age: 17±1 years) during 21 competitive league fixtures (5±3 matches per player).

METHODS

Physical performances were categorised into total distance covered, total low-speed running (0-14.9kmh(-1)) and total high-speed running (15.0-35.0kmh(-1)). These dependent variables were subsequently time averaged into pre-determined periods of 5-, 15- and 45-min duration, and expressed in relative (mmin(-1)) terms to allow direct comparisons between match periods of different lengths. During the 15-min half-time interval players were passive (seated rest).

RESULTS

There was a large reduction in relative total distance covered (effect size - standardised mean difference - 1.85), low-speed running (effect size -1.74) and high-speed running (effect size -1.37) during the opening 5-min phase of the second half (46-50min) when compared to the first half mean (0-45min). When comparing the 51-55 and 56-60-min periods, effect sizes were trivial for relative total distance covered (effect size -0.13; -0.04), low-speed running (effect size -0.10; -0.11) and small/trivial for high-speed running (-0.39; 0.11).

CONCLUSIONS

Using a more robust analytical approach, the findings of this study support and extend previous research demonstrating that players work-rate was markedly lower in the first 5-min after a passive half-time interval, although we observed this phenomenon to be transient in nature. Time-motion analysts might re-consider their data reduction methods and comparators to distinguish within-match player work-rate trends.

The effect of warm-up on intermittent sprint performance and selected thermoregulatory parameters

OBJECTIVES

To investigate the effect of various warm-up intensities based upon individual lactate thresholds on subsequent intermittent sprint performance, as well as to determine which temperature (muscle; T(mu), rectal; T(re) or body; T(b)) best correlated with performance (total work, work and power output of the first sprint, and % work decrement).

DESIGN

Nine male team-sport participants performed five 10-min warm-up protocols consisting of different exercise intensities on five separate occasions, separated by a week.

METHODS

Each warm-up protocol was followed by a 6×4-s intermittent sprint test performed on a cycle ergometer with 21-s of recovery between sprints. T(mu), T(re) and T(b) were monitored throughout the test.

RESULTS

There were no differences between warm-up conditions for total work (J kg⁻¹; P=0.442), first sprint work (J kg⁻¹; P=0.769), power output of the first sprint (W kg⁻¹; P=0.189), or % work decrement (P=0.136), respectively. Moderate to large effect sizes (>0.5; Cohen's d) suggested a tendency for improvement in every performance variable assessed following a warm-up performed at an intensity midway between lactate inflection and lactate threshold. While T(mu), T(re), T(b), heart rate, ratings of perceived exertion and plasma lactate increased significantly during the exercise protocols (P<0.05), there were no significant correlations between T(mu), T(re), and T(b) assessed immediately after each warm-up condition and any performance variable assessed.

CONCLUSIONS

Warm-up performed at an intensity midway between lactate inflection and lactate threshold resulted in optimal intermittent sprint performance. Significant increases in T(mu), T(re) and T(b) during the sprint test did not affect exercise performance between warm-up conditions.

Sling exercise and traditional warm-up have similar effects on the velocity and accuracy of throwing

Throwing is a complex motion that involves the entire body and often puts an inordinate amount of stress on the shoulder and the arm. Warm-up prepares the body for work and can enhance performance. Sling-based exercise (SE) has been theorized to activate muscles, particularly the stabilizers, in a manner beneficial for preactivity warm-up, yet this hypothesis has not been tested. Our purpose was to determine if a warm-up using SE would increase throwing velocity and accuracy compared to a traditional, thrower's 10 warm-up program. Division I baseball players (nonpitchers) (16 men, age: 19.6 ± 1.3, height: 184.2 ± 6.2 cm, mass: 76.9 ± 19.2 kg) volunteered to participate in this crossover study. All subjects underwent both a warm-up routine using a traditional method (Thrower's 10 exercises) and a warm-up routine using closed kinetic chain SE methods (RedCord) on different days separated by 72 hours. Ball velocity and accuracy measures were obtained on 10 throws after either the traditional and SE warm-up regimens. Velocity was recorded using a standard Juggs radar gun (JUGS; Tualatin, OR, USA). Accuracy was recorded using a custom accuracy target. An Analysis of covariance was performed, with the number of throws recorded before the testing was used as a covariate and p < 0.05 was set a priori. There were no statistical differences between the SE warm-up and Thrower's 10 warm-up for throwing velocity (SE: 74.7 ± 7.5 mph, Thrower's 10: 74.6 ± 7.3 mph p = 0.874) or accuracy (SE: 115.6 ± 53.7 cm, Thrower's 10: 91.8 ± 55 cm, p = 0.136). Warming up with SE produced equivalent throwing velocity and accuracy compared to the Thrower's 10 warm-up method. Thus, SE provides an alternative to traditional warm-up.

A single 30-s stretch is sufficient to inhibit maximal voluntary strength

While it has been well established that an acute stretching program can inhibit maximal muscle performance, the amount of stretching needed to produce the deleterious response is unknown. Therefore this study examined the dose-response relationship between acute stretching and strength inhibition. Eighteen college students performed a one repetition maximum (1-RM) test of knee-flexion following 0, 1, 2, 3, 4, 5, or 6 30-s bouts of hamstring stretching held at the limit of toleration. All seven dose variations were done by each subject, with each variation done on a separate day. One week separated each test, and the order of the stretch variations was balanced across the seven testing days. Stretching significantly (p < .05) reduced 1-RM after one 30-s stretch (5.4%), and continued to decrease 1-RM up to and including six 30-s stretches (12.4%). A single 30-s stretch, if held at the limit of toleration, is sufficient to cause an inhibition in a person's 1-RM. Additional bouts of stretching will further decrease the 1-RM, suggesting that multiple mechanisms may be involved in stretch-induced strength inhibition.

Warm-up or stretch as preparation for sprint performance?

Warm-up and stretching are widely used as techniques in preparation for intense physical activity, yet there is little information available to compare their effectiveness in relation to athletic performance. Fourteen elite Under-19 year old rugby league footballers undertook each of four preparation protocols (no preparation, stretching only, warm-up only, warm-up and stretching) in four successive testing sessions. Protocols were randomly allocated to players in a counterbalanced design so that each type of preparation occurred equally on each day of testing. During each session, athletes performed three solo sprint trials at maximum speed. Sprints were of 40-m distance and were electronically timed with wind speed and direction recorded. Preparation involving warm-up resulted in significantly faster sprint times compared to preparations having no warm-up, with a diminishing effect over the three trials. On the first trial, warm-up resulted in a mean advantage of 0.97 m over 40 m. Stretching resulted in a mean disadvantage of 0.18 m on the first trial, and no significant effect overall despite significant wind assistance. Warm-up was effective at improving immediate sprint performance, whereas an equivalent duration of lower limb stretching had no effect.

Warm-up reduces delayed-onset muscle soreness but cool-down does not: a randomised controlled trial

QUESTION

Does warm-up or cool-down (also called warm-down) reduce delayed-onset muscle soreness?

DESIGN

Randomised controlled trial of factorial design with concealed allocation and intention-to-treat analysis.

PARTICIPANTS

Fifty-two healthy adults (23 men and 29 women aged 17 to 40 years).

INTERVENTION

Four equally-sized groups received either warm-up and cool-down, warm-up only, cool-down only, or neither warm-up nor cool-down. All participants performed exercise to induce delayed-onset muscle soreness, which involved walking backwards downhill on an inclined treadmill for 30 minutes. The warm-up and cool-down exercise involved walking forwards uphill on an inclined treadmill for 10 minutes.

OUTCOME MEASURE

Muscle soreness, measured on a 100-mm visual analogue scale.

RESULTS

Warm-up reduced perceived muscle soreness 48 hours after exercise on the visual analogue scale (mean effect of 13 mm, 95% CI 2 to 24 mm). However cool-down had no apparent effect (mean effect of 0 mm, 95% CI -11 to 11 mm).

CONCLUSION

Warm-up performed immediately prior to unaccustomed eccentric exercise produces small reductions in delayed-onset muscle soreness but cool-down performed after exercise does not.

Acute heat exposure increases high-intensity performance during sprint cycle exercise

The purpose of this study was to investigate the effects of acute heat exposure at thermal balance on high-intensity performance during sprint cycle exercise. Nine healthy male subjects were tested in three different, well-controlled environments in an environmental chamber: T (22 degrees C, 65% RH), H1 (30 degrees C, 55% RH) and H2 (35 degrees C, 62% RH), each test being carried out on a different day following a randomized sequence. After 30 min of exposure to the set environment, subjects performed the 30-s sprint cycle exercise. Heart rate, rectal and skin temperatures were measured prior to exercise, at rest, before and after environmental exposure, and after exercise. There were no differences in subjects' core temperature or heart rate prior to exercise. However, skin temperature was significantly higher in hot trials compared with the control throughout the experimental session (P < 0.05). Peak power was significantly higher in the hot environments compared with the control. Mean power was higher only in H2 compared with T (P < 0.05). This difference in power output was the consequence of a faster pedaling cadence in the hot trials (P < 0.05). Plasma ammonia was higher in the hot trials versus control at 4 min post-sprint. No differences in blood lactate levels at 3 min post-sprint were observed between tests. The results of this study suggest that the exposure to hot environment caused an improvement in power output for a single 30-s sprint. This increase in power output was associated with an elevation in plasma ammonia suggestive of an increase in adenine nucleotide loss.

Comparison in the effect of linear polarized near-infrared light irradiation and light exercise on shoulder joint flexibility

OBJECTIVE

This study aimed at comparing the effect of linear polarized near-infrared light irradiation (PL irradiation) and bicycle exercise with 50%HRreserve on the flexibility of the shoulder joint.

DESIGN

Placebo-controlled trial.

SETTING

Twenty-four healthy young adults (10 males: mean+/-SD, age 20.9+/-3.1 y, height 171.0+/-3.9 cm, body mass 63.4+/-3.5 kg and 14 females: age 21.2+/-1.7 y, height 162.0+/-7.8 cm, body mass 56.2+/-7.2 kg).

INTERVENTIONS

PL-irradiation (100%, 1800 mW), placebo-irradiation (10%,180 mW), and light exercise (50%HRreserve) for 10 minutes. OUTCOME MEASUREMENTS AND RESULTS: The shoulder joint angles were measured twice-before and after each intervention. We measured the angles when the right shoulder joint extended forward and flexed backward maximally without support, and analyzed these shoulder joints and range of motion. Trial-to-trial reliability (intraclass correlations) of each joint angle was very high, over 0.98. All joint angles showed significant changes, and values in post-PL-irradiation and postlight exercise were significantly greater than that in postplacebo-irradiation. Shoulder forward flexion and backward extension angles had significantly greater change rates in PL-irradiation and light exercise than placebo-irradiation, and their range of motion angle was in the order of PL-irradiation, light exercise, and placebo-irradiation.

CONCLUSIONS

It is suggested that PL-irradiation produces almost the same effect on shoulder joint range of motion as light exercise.

Models to explain fatigue during prolonged endurance cycling

Much of the previous research into understanding fatigue during prolonged cycling has found that cycling performance may be limited by numerous physiological, biomechanical, environmental, mechanical and psychological factors. From over 2000 manuscripts addressing the topic of fatigue, a number of diverse cause-and-effect models have been developed. These include the following models: (i) cardiovascular/anaerobic; (ii) energy supply/energy depletion; (iii) neuromuscular fatigue; (iv) muscle trauma; (v) biomechanical; (vi) thermoregulatory; (vii) psychological/motivational; and (viii) central governor. More recently, however, a complex systems model of fatigue has been proposed, whereby these aforementioned linear models provide afferent feedback that is integrated by a central governor into our unconscious perception of fatigue. This review outlines the more conventional linear models of fatigue and addresses specifically how these may influence the development of fatigue during cycling. The review concludes by showing how these linear models of fatigue might be integrated into a more recently proposed nonlinear complex systems model of exercise-induced fatigue.

Effect of Warm-Up on Cycle Time Trial Performance

PURPOSE

This study was designed to determine the effect of warm-up on 3-km cycling time trial (TT) performance, and the influence of accelerated VO(2) kinetics on such effect.

METHODS

Eight well-trained road cyclists, habituated to 3-km time trials, performed randomly ordered 3-km TT after a) no warm-up (NWU), b) easy warm-up (EWU) (15 min comprised of 5-min segments at 70, 80, and 90% of ventilatory threshold (VT) followed by 2 min of rest), or c) hard warm-up (HWU) (15 min comprised of 5-min segments at 70, 80, and 90% VT, plus 3 min at the respiratory compensation threshold (RCT) followed by 6 min of rest). VO(2) and power output (SRM), aerobic and anaerobic energy contributions, and VO(2) kinetics (mean response time to 63% of the VO(2) observed at 2 km) were determined throughout each TT.

RESULTS

Three-kilometer TT performance was (P < 0.05) improved for both EWU (266.8 +/- 12.0 s) (-2.8%) and HWU (267.3 +/- 10.4 s) (-2.6%) versus NWU (274.4 +/- 12.1 s). The gain in performance was predominantly during the first 1000 m in both EWU (48% of gain) and HWU (53% of gain). This reflected a higher power output during the first 1000 m in both EWU (384 W) and HWU warm-up (386 W) versus NWU (344 W) trials. The mean response time was faster in both EWU (45 +/- 10 s) and HWU (41 +/- 12 s) versus NWU (52 +/- 13 s) trials. There were no differences in anaerobic power output during the trials, but aerobic power output during the first 1000 m was larger during both EWU (203 W) and HWU (208 W) versus NWU (163 W) trials.

CONCLUSIONS

During endurance events of intermediate duration (4-5 min), performance is enhanced by warm-up irrespective of warm-up intensity. The improved performance is related to an acceleration of VO(2) kinetics.

Diurnal variation in cycling performance: influence of warm-up

We examined the effects of time of day on a cycling time trial with and without a prolonged warm-up, among cyclists who tended towards being high in "morningness". Eight male cyclists (mean +/- s: age = 24.9 +/- 3.5 years, peak power output = 319 +/- 34 W, chronotype = 39 +/- 6 units) completed a 16.1-km time trial without a substantial warm-up at both 07:30 and 17:30 h. The time trial was also completed at both times of day after a 25-min warm-up at 60% of peak power. Power output, heart rate, intra-aural temperature and category ratings of perceived exertion (CR-10) were measured throughout the time trial. Post-test blood lactate concentration was also recorded. Warm-up generally improved time trial performance at both times of day (95% CI for improvement = 0 to 30 s), but mean cycling time was still significantly slower at 07:30 h than at 17:30 h after the warm-up (95% CI for difference = 33 to 66 s). Intra-aural temperature increased as the time trial progressed (P < 0.0005) and was significantly higher throughout the time trials at 17:30 h (P = 0.001), irrespective of whether the cyclists performed a warm-up or not. Blood lactate concentration after the time trial was lowest at 07:30 h without a warm-up (P = 0.02). No effects of time of day or warm-up were found for CR-10 or heart rate responses during the time trial. These results suggest that 16.1-km cycling performance is worse in the morning than in the afternoon, even with athletes who tend towards 'morningness', and who perform a vigorous 25-min warm-up. Diurnal variation in cycling performance is, therefore, relatively robust to some external and behavioural factors.

Morning warming-up exercise--effects on musculoskeletal fitness in construction workers

The aim of the present study was to evaluate the effects on muscle stretchability, joint flexibility, muscle strength and endurance in construction workers of a 3-month period of a 10-min morning warming-up exercise (MWU), performed at the building site every working day. Thirty construction workers participated in the program. Seventeen construction workers at other building sites served as controls. Muscle stretchability, joint flexibility, muscle strength and endurance were measured before and after the program. Significant increase of thoracic and lower back mobility, increase of hamstring and thigh muscle stretchability were seen in the MWU group. A significant difference in back muscle endurance was found due to decreased endurance in the controls. Muscular strength was not influenced by the MWU. The results indicate that a short dose of morning warming-up exercise could be beneficial for increasing or maintaining joint and muscle flexibility and muscle endurance for workers exposed to manual material handling and strenuous working positions.

Comportamento da flexibilidade após 10 semanas de treinamento com pesos

O propósito deste estudo foi analisar o comportamento da flexibilidade de diferentes articulações após 10 semanas de treinamento com pesos (TP). Para tanto, 16 homens (23,0 ± 2,1 anos; 68,0 ± 7,0kg; 178,8 ± 8,7cm) sedentários, mas aparentemente saudáveis, foram aleatoriamente divididos em grupo treinamento (GT, n = 8) e grupo controle (GC, n = 8). O GT foi submetido a 10 semanas consecutivas de TP (três sessões semanais, em dias alternados), ao passo que o GC não se envolveu com a prática de nenhum programa sistematizado de atividades físicas nesse período. Os 11 exercícios que compuseram o programa de TP foram executados em três séries de 8-12 RM. Os movimentos de flexão e extensão do ombro; flexão, extensão e flexão lateral do tronco; flexão e extensão do quadril; flexão e extensão do cotovelo; e flexão do joelho foram utilizados para a análise do comportamento da flexibilidade. ANOVA e ANCOVA para medidas repetidas, seguidas pelo teste post hoc de Tukey, quando P < 0,05, foram utilizadas para o tratamento dos dados. Aumentos significantes na flexibilidade entre os momentos pré e pós-experimento foram encontrados no GT nos movimentos de flexão do ombro (hemicorpo direito, P < 0,05), extensão do quadril (hemicorpo esquerdo, P < 0,05), extensão do tronco (P < 0,05), flexão do tronco (P < 0,05) e flexão lateral do tronco (hemicorpo direito, P < 0,05; hemicorpo esquerdo, P < 0,01). Apesar disso, o efeito da interação grupo vs. tempo foi identificado somente nos movimentos de flexão do cotovelo (hemicorpos direito e esquerdo, P < 0,05), extensão do quadril (hemicorpo esquerdo, P < 0,05) e flexão lateral do tronco (hemicorpo esquerdo, P < 0,01). Assim, os resultados do presente estudo sugerem que as 10 primeiras semanas de prática de TP podem contribuir efetivamente para a preservação ou melhoria dos níveis de flexibilidade observados no período pré-treinamento, em diferentes articulações.

Effect of active warm-up on metabolism prior to and during intense dynamic exercise

PURPOSE

This study investigated whether active warm-up (AW) would increase muscle acetylcarnitine concentration before exercise, thereby reducing the reliance on nonoxidative ATP production during subsequent high-intensity exercise.

METHODS

Six female subjects performed a 30-s sprint at 120% of their maximal power output on an electronically braked cycle ergometer 5 min after undertaking an active warm-up. To exclude any effect of muscle temperature (Tm) on metabolism, AW was compared with control (C), which involved passively heating the muscle to the same temperature as that achieved by active warm-up (37.1 +/- 0.3 vs 37.2 +/- 0.2 degrees C AW and C, respectively).

RESULTS

Active warm-up significantly increased the concentration of acetylcarnitine from 4.5 +/- 1.5 mmol x kg(-1) dry muscle (dm)(-1) at rest to 9.4 +/- 1.6 mmol x kg dm(-1) before the onset of exercise. There was no change in acetylcarnitine concentration in C. During exercise the accumulation of muscle lactate was significantly less in AW compared with C (21.9 +/- 3.8 vs 34.3 +/- 2.3 mmol.kg dm, respectively).

CONCLUSION

The main finding of this study was that there was less accumulation of blood and muscle lactate during intense dynamic exercise preceded by active warm-up, which could not be accounted for by a difference in T between trials immediately before the onset of exercise(m)