The effect of three different warm-up intensities on kayak ergometer performance

Are athletes able to self-select their optimal warm up?

This study aimed to examine whether athletes are able to self-select their optimal warm up and to propose a methodological approach in investigating the effects of warm up on performance. Nine male subjects underwent a free field warm up (FWU) at a self-selected intensity and duration during which heart rate (HR) and rectal temperature (Tre) were monitored. The intensity of this warm up was subsequently estimated from the HR obtained during an incremental test to determine maximal power (Pmax). Performance (cycle time to exhaustion at Pmax), HR and Tre, were then examined following either: NWU (no warm up); RWU (reference warm up based on FWU); RWU-10 (warm up intensity diminished by 10% compared to RWU); and RWU+10 (warm up intensity increased by 10% compared to RWU). Results showed no significant difference in HR (P = 0.37) and Tre increase (P= 0.77) between FWU and RWU. Performance improvement after warm up conditions gave RWU (56%; ie, 5/9 subjects) >RWU-10 (33%; ie, 3/9) >RWU+10 (11%; ie, 1/9) >NWU with significant differences between RWU and NWU (P < 0.01); RWU and RWU+10 (P < 0.01); RWU-10 and NWU (P < 0.01). A warm up intensity ranging from 54-72% Pmax, and inducing an increase in heart rate to 80 +/- 6% HRmax, was found to be optimal. While most athletes were able to self-determine the intensity of their optimal warm up, for others there is still a need for control.

Effect of Acute Static Stretching on Force, Balance, Reaction Time, and Movement Time

PURPOSE

The purpose of the study was to investigate the effect of an acute bout of lower limb static stretching on balance, proprioception, reaction, and movement time.

METHODS

Sixteen subjects were tested before and after both a static stretching of the quadriceps, hamstrings, and plantar flexors or a similar duration control condition. The stretching protocol involved a 5-min cycle warm-up followed by three stretches to the point of discomfort of 45 s each with 15-s rest periods for each muscle group. Measurements included maximal voluntary isometric contraction (MVC) force of the leg extensors, static balance using a computerized wobble board, reaction and movement time of the dominant lower limb, and the ability to match 30% and 50% MVC forces with and without visual feedback.

RESULTS

There were no significant differences in the decrease in MVC between the stretch and control conditions or in the ability to match submaximal forces. However, there was a significant (P < 0.009) decrease in balance scores with the stretch (decreasing 9.2%) compared with the control (increasing 17.3%) condition. Similarly, decreases in reaction (5.8%) and movement (5.7%) time with the control condition differed significantly (P < 0.01) from the stretch-induced increases of 4.0% and 1.9%, respectively.

CONCLUSION

In conclusion, it appears that an acute bout of stretching impaired the warm-up effect achieved under control conditions with balance and reaction/movement time.

Prior heavy exercise enhances performance during subsequent perimaximal exercise

PURPOSE

To test the hypothesis that prior heavy exercise increases the time to exhaustion during subsequent perimaximal exercise.

METHODS

Seven healthy males (mean +/- SD 27 +/- 3 yr; 78.4 +/- 0.7 kg) completed square-wave transitions from unloaded cycling to work rates equivalent to 100, 110, and 120% of the work rate at VO2peak (W-[VO2peak) after no prior exercise (control, C) and 10 min after a 6-min bout of heavy exercise at 50% Delta (HE; half-way between the gas exchange threshold (GET) and VO2peak), in a counterbalanced design.

RESULTS

Blood [lactate] was significantly elevated before the onset of the perimaximal exercise bouts after prior HE (approximately 2.5 vs approximately 1.1 mM; P < 0.05). Prior HE increased time to exhaustion at 100% (mean +/- SEM. C: 386 +/- 92 vs HE: 613 +/- 161 s), 110% (C: 218 +/- 26 vs HE: 284 +/- 47 s), and 120% (C: 139 +/- 18 vs HE: 180 +/- 29 s) of W-VO2peak, (all P < 0.01). VO2 was significantly higher at 1 min into exercise after prior HE at 110% W-VO2peak (C: 3.11 +/- 0.14 vs HE: 3.42 +/- 0.16 L x min(-1); P < 0.05), and at 1 min into exercise (C: 3.25 +/- 0.12 vs HE: 3.67 +/- 0.15; P < 0.01) and at exhaustion (C: 3.60 +/- 0.08 vs HE: 3.95 +/- 0.12 L x min(-1); P < 0.01) at 120% of W-VO2peak.

CONCLUSIONS

This study demonstrate that prior HE, which caused a significant elevation of blood [lactate], resulted in an increased time to exhaustion during subsequent perimaximal exercise presumably by enabling a greater aerobic contribution to the energy requirement of exercise.

Warm up II: performance changes following active warm up and how to structure the warm up

While warm up is considered to be essential for optimum performance, there is little scientific evidence supporting its effectiveness in many situations. As a result, warm-up procedures are usually based on the trial and error experience of the athlete or coach, rather than on scientific study. Summarising the findings of the many warm-up studies conducted over the years is difficult. Many of the earlier studies were poorly controlled, contained few study participants and often omitted statistical analyses. Furthermore, over the years, warm up protocols consisting of different types (e.g. active, passive, specific) and structures (e.g. varied intensity, duration and recovery) have been used. Finally, while many studies have investigated the physiological responses to warm up, relatively few studies have reported changes in performance following warm up. The first part of this review critically analyses reported changes in performance following various active warm-up protocols. While there is a scarcity of well-controlled studies with large subject numbers and appropriate statistical analyses, a number of conclusions can be drawn regarding the effects of active warm up on performance. Active warm up tends to result in slightly larger improvements in short-term performance (<10 seconds) than those achieved by passive heating alone. However, short-term performance may be impaired if the warm-up protocol is too intense or does not allow sufficient recovery, and results in a decreased availability of high-energy phosphates before commencing the task. Active warm up appears to improve both long-term (>/=5 minutes) and intermediate performance (>10 seconds, but <5 minutes) if it allows the athlete to begin the subsequent task in a relatively non-fatigued state, but with an elevated baseline oxygen consumption (VO(2)). While active warm up has been reported to improve endurance performance, it may have a detrimental effect on endurance performance if it causes a significant increase in thermoregulatory strain. The addition of a brief, task-specific burst of activity has been reported to provide further ergogenic benefits for some tasks. By manipulating intensity, duration and recovery, many different warm-up protocols may be able to achieve similar physiological and performance changes. Finally, passive warm-up techniques may be important to supplement or maintain temperature increases produced by an active warm up, especially if there is an unavoidable delay between the warm up and the task and/or the weather is cold. Further research is required to investigate the role of warm up in different environmental conditions, especially for endurance events where a critical core temperature may limit performance.

Warm up I: potential mechanisms and the effects of passive warm up on exercise performance

Despite limited scientific evidence supporting their effectiveness, warm-up routines prior to exercise are a well-accepted practice. The majority of the effects of warm up have been attributed to temperature-related mechanisms (e.g. decreased stiffness, increased nerve-conduction rate, altered force-velocity relationship, increased anaerobic energy provision and increased thermoregulatory strain), although non-temperature-related mechanisms have also been proposed (e.g. effects of acidaemia, elevation of baseline oxygen consumption (.VO(2)) and increased postactivation potentiation). It has also been hypothesised that warm up may have a number of psychological effects (e.g. increased preparedness). Warm-up techniques can be broadly classified into two major categories: passive warm up or active warm up. Passive warm up involves raising muscle or core temperature by some external means, while active warm up utilises exercise. Passive heating allows one to obtain the increase in muscle or core temperature achieved by active warm up without depleting energy substrates. Passive warm up, although not practical for most athletes, also allows one to test the hypothesis that many of the performance changes associated with active warm up can be largely attributed to temperature-related mechanisms.

The influence of pacing strategy on VO2 and supramaximal kayak performance

PURPOSE

The purpose of this study was to investigate the effects of manipulating pacing strategy on VO2 and kayak ergometer performance in well-trained paddlers.

METHODS

Eight well-trained kayak paddlers (500-m time = 115-125 s) first performed a graded exercise test for determination of VO2max and lactate (La-) parameters. On subsequent days and in a random, counterbalanced order, subjects performed a 2-min, kayak ergometer test using either an all-out start or even pacing strategy.

RESULTS

There was a significantly greater peak power (747.6 +/- 152.0 vs 558.3 +/- 110.1 W) and average power (348.5 +/- 47.6 vs 335.5 +/- 44.8 W) using the all-out start strategy, when compared with the even-paced strategy. There was however, no significant difference between the two pacing strategies for peak VO2, accumulated oxygen deficit (AOD), peak [La-], or posttest pH. Using the all-out start, total VO2 was significantly greater (7.3 +/- 0.8 vs 6.9 +/- 0.8 L).

CONCLUSION

The results of this study indicate that 2-min kayak ergometer performance is significantly greater following an all-out start strategy when compared with an even-paced strategy. The improved performance appears to be attributable to faster VO2 kinetics, without a significant change in the total AOD (although the AOD distribution was altered).