Deep-water running: a practical review of the literature with an emphasis on biomechanics

Hydrodynamic Flow Characteristics of a Recirculating Pool: Examining the Ecological Validity for Training and Testing

ABSTRACT

Krajewski, KT, Beethe, AZ, Dever, DE, Johnson, CD, Nindl, BC, Lovalekar, MT, Flanagan, SD, and Connaboy, C. Hydrodynamic flow characteristics of a recirculating pool: examining the ecological validity for training and testing. J Strength Cond Res 37(10): 2023-2031, 2023-Recirculating swimming flumes (RSFs) with elliptical multifeature designs have grown in popularity due to their multifunctionality for rehabilitation and training. Because of their smaller footprint, laboratories have adopted their use to investigate swimming and underwater treadmill running. However, little is known about the hydrodynamic characteristics of these RSFs and how they might influence outcomes. The purpose was to determine hydrodynamic flow characteristics of an RSF at the manufacturers' set "speeds" around the centroid of flow projection. Hydrodynamic velocity profiles were collected through a 3D profiling velocimeter, sampling at 200 Hz in an RSF. Data were collected 0.5 and 1.5 m from the projection channel at designated flume "speeds" of 30-95 (+99) in 5-unit increments. Velocity data were collected for 1 minute per trial (location × speed) to determine mean flow velocity (MFV) for 10, 20, 30, and 40 cm2 cross-sectional areas (CSAs). A two-way ANOVA was conducted comparing CSAs from the surface by distance from the current channel (4 × 2). Separate ANOVAs were conducted to assess differences in MFV across each CSA. Significant differences between flow CSAs indicated that MFV is less for a larger area at the same speed, indicative of variable and turbulent flow characteristics across the respective CSAs. Mean flow velocity was further diminished by distance from the flow channel as supported by the main effect, thus exposing an individual to variant flow velocities simultaneously. Limited stability of the flow velocity centroid could affect swim mechanics making the movement pattern no longer analogous to traditional pool and open water swimming, rather resembling swimming upstream in a river with turbulent flow.

Stress Injuries in the Athlete

Stress fractures are a common injury that present in athletes because of the high intensity and repetitive nature of many sports. These injuries require a high index of suspicion in the treating clinician to allow for timely management. Though most low-risk fractures heal well with conservative management, high-risk stress fractures as well as any fracture in the elite athlete may warrant surgical intervention as well as an augmented treatment and rehabilitation regimen.

Effectiveness of Deep Water Running on Improving Cardiorespiratory Fitness, Physical Function and Quality of Life: A Systematic Review

Deep Water Running (DWR) is a form of aquatic aerobic exercise simulating the running patterns adopted on dry land. Little is known on the effectiveness of DWR despite gaining popularity. The objective of this study is to systematically review the effects of DWR on cardiorespiratory fitness, physical function, and quality of life in healthy and clinical populations. A systematic search was completed using six databases, including SPORTDiscus, MEDLINE, CINAHL, AMED, Embase, and The Cochrane Library, up to February 2022. Eleven studies evaluating the effectiveness of DWR on cardiorespiratory fitness (CRF), physical function, or quality of life (QoL), compared with no interventions (or standard treatment) or land-based trainings were identified. Data relevant to the review questions were extracted by two independent reviewers when means and standard deviations were reported, and standardized mean differences were calculated. A quality assessment was conducted using selected items from the Downs and Black checklist. A total of 11 clinical trials (7 randomized controlled trials) with a total of 287 participants were included. Meta-analyses were not completed due to the high level of clinical and statistical heterogeneity between studies. Compared with land-based training, DWR showed similar effects on CRF with limited studies reporting outcomes of physical function and QoL compared with the no-exercise control group. DWR appears to be comparable to land-based training for improving CRF. The aquatic environment may provide some advantages for off-loaded exercise at high intensity in populations that are weak, injured or in pain, but more studies are required.

Energy Consumption of Water Running and Cycling at Four Exercise Intensities

Water exercise provides a workload in every direction of motion for training in a reduced impact environment. The selection of an appropriate physical activity and an individual exercise prescription are essential to obtain training effects. The aim of the present study was to determine individualised relative exercise intensities at four speeds of motion for water cycling and water running. Running was tested both in buoyancy and with the feet in contact with the bottom of the pool. To this purpose, gas exchanges, heart rate, and blood lactate were measured in each test session. Fourteen active, healthy females (23.2 ± 1.6 years) underwent a dry land maximal incremental protocol to exhaustion on a treadmill and hydrobike (HB); they engaged in water running with ground contact (RC) and water running suspended (RS) tests in a swimming pool at 30, 40, 50, and 60 cycles per minute (cpm), submerged at the individual xiphoid level. The four motion speeds of the three water exercise modalities ranged from 50% to 95% of the maximal heart rate and the maximal oxygen uptake, representing a moderate-to-vigorous training stimulus. RS elicited the lowest oxygen consumption, whereas HB demanded the significantly highest oxygen consumption and presented the highest blood lactate accumulation, with vigorous intensity being reached at 50 cpm and near maximal intensity at 60 cpm. It appears that water cycling could be more suitable for athletic training, whereas water running could be more appropriate for health and fitness purposes.

Calf Strain in Athletes

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Calf strain is a common condition. In high-performance athletes, calf strain contributes to a substantial absence from competition.

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Player age and history of a calf strain or other leg injury are the strongest risk factors for calf strain injury and reinjury.

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Although the diagnosis is often clinical, magnetic resonance imaging and ultrasound are valuable to confirm the location of the strain and the grade of injury.

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Nonoperative treatment is effective for most calf strain injuries. Operative management, although rarely indicated, may be appropriate for severe cases with grade-III rupture or complications.

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Further investigation is necessary to elucidate the benefits of blood flow restriction therapy, deep water running, lower-body positive pressure therapy, platelet-rich plasma, and stem cell therapy for calf strain rehabilitation.

Lower-Body Aquatic Training Prescription for Athletes

ABSTRACT

Holmberg, PM, Gorman, AD, Jenkins, DG, and Kelly, VG. Lower-body aquatic training prescription for athletes. J Strength Cond Res 35(3): 859-869, 2021-Traditionally prescribed to manage various medical ailments and promote healing, aquatic immersion may provide a favorable environment to undertake preparatory training tasks given its profound biological effects that extend across most homeostatic systems. In addition to understanding these effects, which are related to the fundamental principles of hydrodynamics, there is a need to consider the acute physiomechanical responses to alterations of key constraints associated with particular preparatory tasks. Evidence suggests that the manipulation of different constraints during aquatic training can enable a unique setting to complement, supplement, or supplant land-based programming to maintain or improve physical capacities in athletes without exacerbating physiological stress. Thus, this article focuses on the interplay of constraints and their associated outcomes to provide information that can be used to program lower-body aquatic training for athletes. In addition, the aim of the article is to summarize the literature on aquatic training to highlight the outcomes that occur when certain constraints are manipulated.

Comparing the effects of aquatic exercises with or without high intensity on the functional status, muscular endurance, and performance of patients with chronic low back pain

BACKGROUND

The prevalence of low back pain is lower when physical fitness (aerobic and muscular) is higher. Strength exercises are important for subjects with low back pain, but there are few studies on the inclusion of aerobic exercise in low back pain programs. The aim of this study was to compare the effects of aquatic exercises with or without high-intensity component on the functional status, lumbar and abdominal muscle endurance, and performance of subjects with chronic low back pain.

METHODS

Forty-eight volunteers between 20 and 60 years old were randomly allocated to an experimental group AEDWR (aquatic exercises plus deep-water running group, N.=25) or to a control group AE (aquatic exercises only group, N.=23). The dependent variables included functional status (Repeated Sit-to-Stand test), lumbar (Sorensen test) and abdominal (One Minute Abdominal test) muscle endurance, and physical performance (Maximum Physical Fitness test), which were measured before and after the 9-week intervention and at 21 weeks of follow-up.

RESULTS

Lumbar endurance was higher in the AEDWR group at the end of the treatment, with a mean difference (MD) of 43.2 seconds, 95% confidence intervals (CI) (9.6; 76.7), P=0.01, d̅=0.74, and better in the follow-up with MD=40.2 seconds, 95% CI (7.1; 73.3), P=0.02, d̅=0.71, than in the AE group. Participant performance also improved on the 9^th week in the AEDWR group, with an MD=0.53 kgf, 95% CI (0.008; 0.98), P=0.02, d̅=0.60.

CONCLUSIONS

The addition of deep-water running exercise to aquatic exercises improved lumbar muscle endurance and performance when compared with aquatic exercises only, and this effect was maintained during the follow-up to lumbar muscle endurance.

Effectiveness of additional deep-water running for disability, lumbar pain intensity, and functional capacity in patients with chronic low back pain: A randomised controlled trial with 3-month follow-up

BACKGROUND

Aquatic exercise (AQE) programme is commonly used as an alternative to the chronic low back pain (CLBP) treatment. The addition of aquatic aerobic exercises to AQE may be beneficial to patients with CLBP.

DESIGN

Randomised controlled trial.

OBJECTIVES

To assess the effectiveness of AQE with the addition of aerobic exercise - deep-water running (DWR) - compared to exclusive AQE in improving disability, lumbar pain intensity, and functional capacity in patients with CLBP.

METHODS

Fifty-four adult patients with CLBP were randomised either to the experimental group (AQE + DWR) or the control group (AQE). An assessor who was blinded to the group allocation performed both pre- and post-interventions assessments. Both treatments lasted 9 weeks, with a 3-month follow-up. The primary outcome was disability, as evaluated using the Roland Morris Disability Questionnaire. The secondary outcomes were pain and functional capacity; pain was assessed using a visual analogue scale (VAS), and functional capacity (travelled distance) was measured using the 6-min walk test (6WT).

RESULTS

A significant difference in pain was observed between groups after intervention in favour of DWR (mean difference -1.3 cm [95% confidence interval (CI) -2.17 to -0.45], d‾ = 0.80 [95% CI 0.22 to 1.33]).

CONCLUSION

Treatment with DWR was effective in the short term for achieving the desired outcome of pain reduction when compared with AQE only but not for disability and functional capacity.

A Study on Trunk Muscle Activation of 2 Deep Water Running Styles (High-Knee and Cross-Country Style) and Land Walking

Context: Deep water running (DWR) is an aquatic aerobic exercise which involves running in water without the feet touching the bottom of the pool, and it may involve different activation of trunk muscles compared with running or walking on land. This form of exercise is gradually being adopted as a form of therapeutic exercise for people with low back pain. It is proposed that different types of running or walking in water may be a more comfortable form of training for the trunk and abdominal muscles compared with exercising on dry land. Objectives: This study aimed to examine the trunk muscle activation in DWR in 2 different styles—high knee style and cross-country style, and these were compared with walking on land. Participants: Eleven healthy individuals (2 females and 9 males, mean age = 24 [4.6]) were recruited for this study. Outcome Measures: Surface electromyography was used to examine the activities of the right transversus abdominis, rectus abdominis, lumbar multifidus, and lumbar erector spinae muscles in 5 conditions: static standing on land and in water, running in deep water with high knee and cross-country styles, and finally walking on a treadmill. Results: The percentage of maximal voluntary contraction of the transversus abdominis was significantly higher for both running styles in DWR, compared with that of static standing in water. Comparing directly the 2 styles, muscle activity was higher with a high knee action compared to without. The activation of transversus abdominis during high-knee DWR was comparable with that during treadmill walking and this may have clinical implications. Conclusion: The results of this study confirmed that running in deep water with a high knee action activated trunk muscles differently compared with standing or walking on land.

The features of muscle activity during chair standing and sitting motion in submerged condition

This study aimed to measure muscle activity and motion kinematics during chair-based exercises under submerged and non-submerged conditions. Twelve healthy men performed chair-based standing and sitting movements. Surface electrodes were attached at the tibialis anterior, gastrocnemius, rectus femoris, biceps femoris, rectus abdominis, and erector spinae. The ankle, knee, and hip joint angles and forward inclination angle of the trunk segment in the sagittal plane were calculated. The mean muscle activities during both movements in the submerged condition for the entire motion were lower than those in the non-submerged condition except in the tibialis anterior and biceps femoris during the sitting movement (in the standing exercise, rectus femoris: 14.1% and 5.2%; and erector spinae: 18.3% and 13.6% in non-submerged and submerged conditions, respectively; and in the sitting exercise, rectus femoris: 12.1% and 4.5% and erector spinae: 12.9% and 9.9% in the non-submerged and submerged conditions, respectively). However, the integrated muscle activity in submerged conditions was similar or higher to that in non-submerged conditions during both movements, except for the rectus femoris. This was mainly due to the increased duration of motion (44.3% and 39.9% longer for standing and sitting exercises in submerged conditions, respectively, compared with non-submerged conditions). The hip joint flexion at the beginning and end of movement and forward inclination angles of the trunk segment at the beginning of the movement in the submerged condition were larger than those in the non-submerged condition during both movements (hip: 126.1° and 111.5° at the beginning, 182.3° and 178.4° at the end and trunk: 2.7° and 17.4° at the beginning in non-submerged and submerged conditions for the standing exercise, respectively; hip: 182.4° and 178.0° at the beginning, 125.9° and 111.1° at the end and trunk: 2.2° and 16.9° at the end in non-submerged and submerged conditions for the sitting exercise, respectively). Reduced or similar muscle activity but similar or higher muscular effort was observed in the submerged condition for all the muscles except the rectus femoris, with the upper body inclined forward. These findings could have beneficial implications for the prescription of exercise and rehabilitation regimens.

The Properties of Water and their Applications for Training

The biological effects of immersion in water, which are related to the fundamental principles of hydrodynamics, may be beneficial in certain training contexts. The effects and physical properties of water, such as density, hydrostatic pressure and buoyancy are highly useful resources for training, when used as a counterbalance to gravity, resistance, a compressor and a thermal conductor. Not only does the aquatic medium enable a wider range of activities to be used in a context of low joint impact, but it also constitutes a useful tool in relation to sports rehabilitation, since it allows the athlete to return to training earlier or to continue with high-intensity exercise while ensuring both low joint impact and greater comfort for the individual concerned. Moreover, this medium enables the stimulation of metabolic and neuromuscular systems, followed by their corresponding physiological adaptations allowing both to maintain and improve athletic performance. Hydrotherapy can also play a beneficial role in an athlete’s recovery, helping to prevent as well as treat muscle damage and soreness following exercise.

Management and prevention of bone stress injuries in long-distance runners

SYNOPSIS

Bone stress injury (BSI) represents the inability of bone to withstand repetitive loading, which results in structural fatigue and localized bone pain and tenderness. A BSI occurs along a pathology continuum that begins with a stress reaction, which can progress to a stress fracture and, ultimately, a complete bone fracture. Bone stress injuries are a source of concern in long-distance runners, not only because of their frequency and the morbidity they cause but also because of their tendency to recur. While most BSIs readily heal following a period of modified loading and a progressive return to running activities, the high recurrence rate of BSIs signals a need to address their underlying causative factors. A BSI results from disruption of the homeostasis between microdamage formation and its removal. Microdamage accumulation and subsequent risk for development of a BSI are related both to the load applied to a bone and to the ability of the bone to resist load. The former is more amenable to intervention and may be modified by interventions aimed at training-program design, reducing impact-related forces (eg, instructing an athlete to run "softer" or with a higher stride rate), and increasing the strength and/or endurance of local musculature (eg, strengthening the calf for tibial BSIs and the foot intrinsics for BSIs of the metatarsals). Similarly, malalignments and abnormal movement patterns should be explored and addressed. The current commentary discusses management and prevention of BSIs in runners. In doing so, information is provided on the pathophysiology, epidemiology, risk factors, clinical diagnosis, and classification of BSIs.

LEVEL OF EVIDENCE

Therapy, level 5.

Phases of rehabilitation

Rehabilitation is easy to do badly and difficult to do well. Many people are involved in the process, and must act as a team to support the patient with good communication and teamwork. The whole process can be satisfying to all concerned when dealing with motivated and enthusiastic patients. Measuring the process is achievable and gives credibility and support to the initial hypothesis of the individual's rehabilitation program. Rehabilitation involves creativity using science and art, with the end result being the patient's return to a normal life or ability to excel within their sport.