Cardiorespiratory response to low-intensity walking in water and on land in elderly women

Kinematic analysis of gait in an underwater treadmill using land-based Vicon T 40s motion capture cameras arranged externally

Aquatic therapy for rehabilitation can be performed in a variety of environments, which can vary from a traditional swimming pool to a self-contained underwater treadmill. While kinematic analysis has been performed in large volume swimming pools using specific underwater motion capture systems, researchers may only have access to a land-based motion-capture system, which is not waterproof. Additionally, underwater motion capture systems may not fit within the confines of a smaller underwater treadmill. Thus, the purpose of this study was to design and analyze methodology to quantify lower limb kinematics during an aquatic treadmill session, using a land-based motion capture system. Kinematics of lower limb motion at different speeds was studied while walking on an underwater treadmill in comparison to walking on the same treadmill without water (empty tank). The effects of the presence of water on walking kinematics was analyzed and interpreted using parametric and non-parametric testing procedures. The results suggest significant influences of speed on knee and ankle angles (p < 0.05) in both dryland and aquatic scenarios. Knee and ankle angle measures revealed no significant differences between the dryland and water treadmill scenarios (p > 0.05). The increased time requirement in water for the full gait cycle found in this study indicates influence of resistive effects. This finding can be especially suited for muscle strengthening and stabilizing treatments for lower limbs. Also, a framework was developed to realize a potential methodology to use land-based motion capture cameras to successfully analyze the kinematics of gait in constrained aquatic volumes.

Relationship between Oxygen Uptake, Heart Rate, and Perceived Effort in an Aquatic Incremental Test in Older Women

Different parameters can be used to control the intensity of aerobic exercises, a choice that should consider the population and exercise environment targeted. Therefore, our study aimed to verify the relationship between oxygen uptake (VO₂), heart rate (HR), rating of perceived exertion (RPE), and cadence during an aquatic incremental test in older women. Nine older women (64.3 ± 4.4 years) engaged in a water-based aerobic training performed an aquatic incremental test using the stationary running exercise (cadence increases of 15 b·min⁻¹ every 2 min) until participants’ volitional exhaustion. VO₂, HR, and RPE data were measured, and the percentage of peak VO₂ (%VO_2peak) and percentage of maximal HR (%HR_max) were calculated. Linear and polynomial regression analyses were performed (α = 0.05). Polynomial regressions revealed the best adjustments for all analyses. Data showed a significant relationship (p < 0.001) between %VO_2peak and %HR_max (r = 0.921), %VO_2peak and RPE (r = 0.870), and %HR_max and RPE (r = 0.878). Likewise, significant relationships between cadence (p < 0.001) and %VO_2peak (r = 0.873), %HR_max (r = 0.874), and RPE (r = 0.910) were also observed. In summary, the physiological, subjective, and mechanical variables investigated were highly associated during an aquatic incremental test to exhaustion in older women. Therefore, these different parameters can be employed to adequately prescribe water-based programs according to preference and availability.

The effects of breathing exercises in comparison with other exercise programs on cardiorespiratory fitness among healthy female college students

BACKGROUND

We wished to determine the effects of breathing exercises (BE) on endurance performance compared to those of different fitness training programmes.

METHODS

Endurance was measured by the Cooper 12-minute Run Test and voluntary breath-holding time test before and after the training period. Altogether 69 healthy female college students were assigned into four groups. The first group (N.=15) participated in a breathing-exercise programme (BE). The 3 intensity training groups included constant-training (CT; N.=22), interval-training (IT; N.=17), and Fartlek-training groups (FT; (N.=15). All programmes were conducted for one hour twice a week for 7 weeks.

RESULTS

The results of the Cooper test improved significantly in all four groups (P<0.01). The voluntary breath-holding time test showed significant increase in all groups but the CT group. In the BE group the rate of improvement was 9.23% (P=0.014). In the FT group the intensity was 75-85% of maximal heart rate (HRmax), the rate of improvement was 15.2% (P=0.011). In the IT group, the percentage of increase was 9.94% (P=0.039). Finally, the CT resulted in an improvement 8.45% (P=0.063).

CONCLUSIONS

Results derived from the present study suggest that BE may be an effective alternative to improve endurance performance in healthy female college students.

Prediction of ground reaction forces while walking in water

Despite being a key concept in rehabilitation, controlling weight-bearing load while walking, following lower limb injury is very hard to achieve. Walking in water provides an opportunity to prescribe load for people who have pain, weakness or weight bearing restrictions related to stages of healing. The aim of this experimental study was to evaluate and validate regression models for predicting ground reaction forces while walking in water. One hundred and thirty seven individuals (24±5 years, 1.71±0.08 m and 68.7±12.5 kg) were randomly assigned to a regression group (n = 113) and a validation group (n = 24). Trials were performed at a randomly assigned water depth (0.75 to 1.35 m), and at a self-selected speed. Independent variables were: immersion ratio, velocity, body mass, and waist, thigh and leg circumferences. Stepwise regression was used for the prediction of ground reaction forces and validation included agreement and consistency statistical analyses. Data from a force plate were compared with predicted data from the created model in the validation group. Body mass, immersion ratio, and velocity independently predicted 95% of the vertical and resultant ground reaction force variability, while, together, velocity and thigh circumference explained 81% of antero-posterior ground reaction force variability. When tested against the data measured in validation samples, the models output resulted in statistically similar values, intraclass correlation coefficients ranging from 0.88 to 0.90 and standard errors of measurement, 11.8 to 42.3 N. The models introduced in this study showed good predictive performance in our evaluation procedures and may be considered valid in the prediction of vertical, antero-posterior and resultant ground reaction forces while walking in water. All predictive variables can be easily determined in clinical practice. Future studies should focus on the validation of these models in specific populations.

The effects of ankle weight loading on the walking factors of adults without symptoms

The purpose of this study was to evaluate the components of walking adults who have no symptoms by integrating the temporal and spatial walking variables obtained from the GAITRite system. The following describes previous debates on weight-loaded walking training. The conclusion was as follows. First, there was a significant difference in walking distance between the 0% group and 1% group and between the 1% group and 2% group (P<0.05). Sencond, there was a significant difference in walking velocity between the 0% group and 1% group and between the 0% group and 2% group (P<0.05). Third, there was a significant difference in walking cadence between the 0% group and 1% group, between the 1% group and 2% group, and between the 0% group and 2% group (P<0.05). These study results indicate that diverse amounts of weight loading can be effective for enhancing the walking factors of adults without symptoms.

Treadmill walking in water induces greater respiratory muscle fatigue than treadmill walking on land in healthy young men

The purpose of the present study was to investigate the effect of walking in water on respiratory muscle fatigue compared with that of walking on land at the same exercise intensity. Ten healthy males participated in 40-min treadmill walking trials on land and in water at an intensity of 60% of peak oxygen consumption. Respiratory function and respiratory muscle strength were evaluated before and after walking trials. Inspiratory muscle strength and forced expiratory volume in 1 s were significantly decreased immediately after walking in water, and expiratory muscle strength was significantly decreased immediately and 5 min after walking in water compared with the baseline. The decreases of inspiratory and expiratory muscle strength were significantly greater compared with that after walking on land. In conclusion, greater inspiratory and expiratory muscle fatigue was induced by walking in water than by walking on land at the same exercise intensity in healthy young men.

Metabolic and cardiovascular responses during aquatic exercise in water at different temperatures in older adults

PURPOSE

The aim of this study was to investigate the physiological responses during upper-body aquatic exercises in older adults with different pool temperatures.

METHOD

Eleven older men (aged 65 years and older) underwent 2 identical aquatic exercise sessions that consisted of 3 upper-body exercises using progressive intensities (30, 35, and 40 metronome beat · min(- 1)) on separate visits. Water temperatures for the visits were 28°C (cold water [CW]) and 36°C (hot water [HW]), and water depth ranged from 1.2 m to 1.4 m. Measurements for heart rate (HR), blood pressure (BP), oxygen consumption (VO2), and rate of perceived exertion (RPE) were compared between the CW and HW conditions.

RESULTS

The comparison between temperatures showed a higher HR response during exercise in HW, particularly when participants exercised at the highest intensities. During a 30-min postexercise period in resting conditions, HR was statistically significantly higher for the HW condition compared with the CW condition, with a large effect size (15.9%, d = 1.23). Systolic and diastolic BPs were found to be lower for the HW condition ( - 7.2%, d = - 0.60; - 10.1%, d = - 0.65), while VO2 and RPE showed no differences. The effect size between double products (HR · systolic BP) for the 2 conditions was small (CW = 8,649 ± 1,287, HW = 9,340 ± 1,672; d = 0.36), suggesting similar myocardial oxygen requirements.

CONCLUSION

This study showed that HR response was higher in an HW condition for older men. Warmer environments may add additional stressors to the body, which may impact training strategies and should be considered when estimating the effort of performing aquatic exercise.

The effects of landed and aquatic treadmill walking at moderate intensity on heart rate, energy expenditure and catecholamine

PURPOSE

The present study was to examine whether or not the appropriate exercise intensity of water-walking could be accurately prescribed by land-based walking speed.

METHODS

Using a crossover design, nine healthy male college students completed bouts of walking for thirty minutes at 100m/min, 50m/min, respectively, on land and water treadmills. Heart rate (HR), ratings of perceived exertion (RPE), energy expenditure, blood lactic acid and catecholamine concentration were measured. Two-way repeated measured ANOVA was used with the SPSS program for data analysis.

RESULTS

HR (P < 0.001), RPE (P < 0.001), energy expenditure (P < 0.001), blood lactic acid (P < 0.001) and epinephrine concentration (P < 0.05) were significantly increased during walking both in water and on land. The change of HR was significantly lower at 50min/m in water than 100min/m on land (P < 0.01). There were no significant interaction effects for RPE, energy expenditure, blood lactic acid and catecholamine concentration, but these variables were slightly lower in water than on land. These results indicated that the use of land walking speed-based prescriptive norms would underestimate the physiological cost in water walking at the moderate intensity.

CONCLUSION

Therefore, approximately two-half of the speed would be needed to walk in water in order to obtain the same level of physiological load as during treadmill walking at the moderate intensity.

Physiological and biomechanical responses to walking underwater on a non-motorised treadmill: effects of different exercise intensities and depths in middle-aged healthy women

Non-motorised underwater treadmills are commonly used in fitness activities. However, no studies have examined physiological and biomechanical responses of walking on non-motorised treadmills at different intensities and depths. Fifteen middle-aged healthy women underwent two underwater walking tests at two different depths, immersed either up to the xiphoid process (deep water) or the iliac crest (shallow water), at 100, 110, 120, 130 step-per-minute (spm). Oxygen consumption (VO2), heart rate (HR), blood lactate concentration, perceived exertion and step length were determined. Compared to deep water, walking in shallow water exhibited, at all intensities, significantly higher VO2 (+13.5%, on average) and HR (+8.1%, on average) responses. Water depth did not influence lactate concentration, whereas perceived exertion was higher in shallow compared to deep water, solely at 120 (+40%) and 130 (+39.4%) spm. Average step length was reduced as the intensity increased (from 100 to 130 spm), irrespective of water depth. Expressed as a percentage of maximum, average VO2 and HR were: 64-76% of peak VO2 and 71-90% of maximum HR, respectively at both water depths. Accordingly, this form of exercise can be included in the "vigorous" range of exercise intensity, at any of the step frequencies used in this study.

Effects of aquatic backward locomotion exercise and progressive resistance exercise on lumbar extension strength in patients who have undergone lumbar diskectomy

OBJECTIVE

To compare the effects of aquatic backward locomotion exercise and progressive resistance exercise with a machine on lumbar extension strength in patients who have undergone diskectomy for a lumbar disk herniation.

DESIGN

Prospective comparative study.

SETTING

Department of Kinesiology at a state university.

PARTICIPANTS

Male patients (N=30) with disk herniation at spinal levels L3 to S1 completed this study as subjects.

INTERVENTION

After the diskectomy for a lumbar disk herniation, all patients had 6 weeks of rest time. At the end of the rest period, the aquatic backward locomotion exercise and progressive resistance exercise groups, respectively, started first 6 weeks of underwater training and lumbar extension training twice per week. After completion of the first 6-week training, subjects participated in a second 6-week training. After the whole 12-week training, subjects had no training for 6 weeks (detraining) and a follow-up 6-week training (retraining). The control (CON) group did not undergo any training.

MAIN OUTCOME MEASURES

For each test, maximum voluntary isometric lumbar extension strength was measured in 7 trunk positions (72 degrees , 60 degrees , 48 degrees , 36 degrees , 24 degrees , 12 degrees , and 0 degrees of the trunk angle).

RESULTS

The progressive resistance exercise and aquatic backward locomotion exercise groups showed increases in lumbar extension strength after the first 6-week training, although they were not statistically different from the CON group. After a second 6-week training, the progressive resistance exercise and aquatic backward locomotion exercise groups showed statistically significant increases in their strength levels as compared with the CON group. After the detraining period, the strength levels of the progressive resistance exercise and aquatic backward locomotion exercise groups did not statistically differ from the CON group. After the retraining period, the progressive resistance exercise and aquatic backward locomotion exercise groups showed increases in their strength levels, which were different from that of the CON group.

CONCLUSIONS

The results obtained suggested that the aquatic backward locomotion exercise is as beneficial as progressive resistance exercise for improving lumbar extension strength in patients after lumbar diskectomy surgery.

Effects of musical cadence in the acute physiologic adaptations to head-out aquatic exercises

The purpose of this study was to analyze the relationships between musical cadence and the physiologic adaptations to basic head-out aquatic exercises. Fifteen young and clinically healthy women performed, immersed to the breast, a cardiovascular aquatic exercise called the "rocking horse." The study design included an intermittent and progressive protocol starting at a 90 b.min(-1) rhythm and increasing every 6 minutes, by 15 b.min(-1), up to 195 b.min(-1) or exhaustion. The rating of perceived effort (RPE) at the maximal heart rate achieved during each bout (HRmax), the percentage of the maximal theoretical heart rate estimated (%HRmax), and the blood lactate concentration ([La-]) were evaluated. The musical cadence was also calculated at 4 mmol.L(-1) of blood lactate (R4), the RPE at R4 (RPE@R4), the HR at R4 (HR@R4), and the %HRmax at R4 (%HRmax@R4). Strong relationships were verified between the musical cadence and the RPE (R2 = 0.85; p < 0.01), the HRmax (R2 = 0.66; p < 0.01), the %HRmax (R = 0.61; p < 0.01), and the [La-] (R2 = 0.54; p < 0.01). The R4 was 148.13 +/- 17.53 b.min, the RPE@R4 was 14.53 +/- 2.53, the HR@R4 was 169.33 +/- 12.06 b.min, and the %HRmax@R4 was 85.53 +/- 5.72%. The main conclusion is that increasing musical cadence created an increase in the physiologic response. Therefore, instructors must choose musical cadences according to the goals of the session they are conducting to achieve the desired intensity.

The relative cost of bent-hip bent-knee walking is reduced in water

The debate about how early hominids walked may be characterised as two competing hypotheses: They moved with a fully upright (FU) gait, like modern humans, or with a bent-hip, bent-knee (BK) gait, like apes. Both have assumed that this bipedalism was almost exclusively on land, in trees or a combination of the two. Recent findings favoured the FU hypothesis by showing that the BK gait is 50-60% more energetically costly than a FU human gait on land. We confirm these findings but show that in water this cost differential is markedly reduced, especially in deeper water, at slower speeds and with greater knee flexion. These data suggest that the controversy about australopithecine locomotion may be eased if it is assumed that wading was a component of their locomotor repertoire and supports the idea that shallow water might have been an environment favourable to the evolution of early forms of "non-optimal" hominid bipedalism.

Comparison of maximal and spontaneous speeds during walking on dry land and water

The aim of this study was to quantify spontaneous and maximal speeds on dry land and in water, in four modalities of walking [forward (F), backward (B) and lateral walking (L)], with chest immersion level. Lateral walking was studied with the upper limbs of the subject alongside the body with hands placed on the lateral face of the thighs (L1) and upper limbs tightened behind the back with the hands joined (L2). 16 males (age 22.8+/-1.8 years, height 178.1+/-6.1cm, body mass 73.5+/-6.6 kg) and 15 females (age 22.8+/-2.1 years, height 171.5+/-5.8 cm, body mass 69.2+/-9.3 kg) were evaluated using the four modalities of walking on dry land and in water. The speed increments between spontaneous and maximal speeds on dry land for F, B and L1 and L2 were 60.2%, 60.9%, 64.3% and 65.3% for males and 47.3%, 48.3%, 44.5% and 53.1% for females. In the water, these variation values for F, B, L1 and L2 for males were 44.6%, 26.1%, 48.8%, and 42.1%. The values for females were 31.7%, 21.6%, 32.8%, and 34.6%. Spontaneous and maximal speeds of walking were substantially reduced in water with the chest immersed, compared to speeds on dry land for the four modalities and the two genders. These findings may be used by therapists who utilize the various modalities of walking in aquatherapy.

Caminhada em ambiente aquático e terrestre: revisão de literatura sobre a comparação das respostas neuromusculares e cardiorrespiratórias

O objetivo deste estudo foi realizar uma revisão de literatura sobre a comparação das respostas neuromusculares e cardiorrespiratórias durante a caminhada em meio aquático e em meio terrestre. As respostas foram apresentadas para a caminhada em piscina rasa e para a caminhada em piscina funda. Em relação à caminhada em piscina rasa, as respostas neuromusculares (sinal EMG) e cardiorrespiratórias (FC e VO2) são muito dependentes da velocidade do exercício. As respostas neuromusculares podem ser menores no meio aquático quando a velocidade da caminhada é menor nesse ambiente. Por outro lado, quando o exercício é realizado com velocidades similares, a atividade dos músculos propulsores pode ser superior durante a caminhada aquática. Da mesma forma, respostas cardiorrespiratórias maiores são registradas no exercício aquático quando velocidades similares de caminhada são utilizadas. Contudo, com velocidades menores, essas respostas são semelhantes ou menores que as encontradas em meio terrestre. No que diz respeito à caminhada em piscina funda, as respostas neuromusculares diferem daquelas encontradas durante a caminhada em meio terrestre devido à ausência das forças de reação com o solo. Essa característica possivelmente modifica os músculos envolvidos na produção de força propulsiva nesse exercício. Além do mais, durante a caminhada em piscina funda, as respostas cardiorrespiratórias parecem sempre mais baixas devido à grande redução no peso hidrostático e à menor atividade dos músculos posturais e pela utilização do cinturão flutuador nessa modalidade.

Electromyographic Analysis of Walking in Water in Healthy Humans

This study was designed to describe and clarify muscle activities which occur while walking in water. Surface electromyography (EMG) was used to evaluate muscle activities in six healthy subjects (mean age, 23.3 +/- 1.4 years) while they walked on a treadmill in water (with or without a water current) immersed to the level of the xiphoid process, and while they walked on a treadmill on dry land. The trials in water utilized the Flowmill which has a treadmill at the base of a water flume. Integrated EMG analysis was conducted for the quantification of muscle activities. In order to calculate the %MVC, the measurement of maximal voluntary contraction (MVC) of each muscle was made before the gait analysis, thus facilitating a comparison of muscle activities while walking in water with those on dry land. The %MVCs obtained from each of the tested muscles while walking in water, both with and without a water current, were all found to be lower than those obtained while walking on dry land at a level of heart rate response similar to that used when walking on dry land. Furthermore, the %MVCs while walking in water with a water current tended to be greater when compared to those while walking in water without a water current. In conclusion, the present study demonstrated that muscle activities while walking in water were significantly decreased when compared to muscle activities while walking on dry land, that muscle activities while walking in water tended to be greater with a water current than without, and that the magnitude of the muscle activity in water was relatively small in healthy humans. This information is important to design water-based exercise programs that can be safely applied for rehabilitative and recreational purposes.

Body temperature, oxygen uptake and heart rate during walking in water and on land at an exercise intensity based on RPE in elderly men

The purpose of this study was to clarify the characteristics of the physiological response that occurs while walking in water and on land at an exercise intensity based on the rating of perceived exertion (RPE) in elderly men. Nine elderly men ranging from 66-70 years of age participated in this study as subjects. The actual trials consisted of walking for 20 minutes in 31 degrees C and 35 degrees C water on an underwater treadmill. The water depth of the treadmill corresponded to the level of the xiphoid process in the subject. The same subjects performed on-land walking using a moving belt treadmill for 20 minutes at a room temperature of 27 degrees C. The exercise intensity during walking in the two water trials and the on-land trial was the same "somewhat hard" measured on the basis of the subject's RPE rating of 13. There was no significant difference between the subjects' rectal temperatures among the three trials. The mean skin temperature and mean body temperature while walking for 20 minutes in 35 degrees C water were significantly higher (P<0.01) than in 31 degrees C water and on land. There were no significant differences in oxygen uptake and heart rate among the two trials in water and the on-land trial. The above results suggest that the exercise intensity based on a subject's RPE may be an effective index for the prescription of thermoneutral water walking in the same way that it is for land walking in the elderly.