The heart of the senior oarsman: an echocardiographic evaluation

The physiology of rowing with perspective on training and health

PURPOSE

This review presents a perspective on the expansive literature on rowing.

METHODS

The PubMed database was searched for the most relevant literature, while some information was obtained from books.

RESULTS

Following the life span of former rowers paved the way to advocate exercise for health promotion. Rowing involves almost all muscles during the stroke and competition requires a large oxygen uptake, which is challenged by the pulmonary diffusion capacity and restriction in blood flow to the muscles. Unique training adaptations allow for simultaneous engagement of the legs in the relatively slow movement of the rowing stroke that, therefore, involves primarily slow-twitch muscle fibres. Like other sport activities, rowing is associated with adaptation not only of the heart, including both increased internal diameters and myocardial size, but also skeletal muscles with hypertrophy of especially slow-twitch muscle fibres. The high metabolic requirement of intense rowing reduces blood pH and, thereby, arterial oxygen saturation decreases as arterial oxygen tension becomes affected.

CONCLUSION

Competitive rowing challenges most systems in the body including pulmonary function and circulatory control with implication for cerebral blood flow and neuromuscular activation. Thus, the physiology of rowing is complex, but it obviously favours large individuals with arms and legs that allow the development of a long stroke. Present inquiries include the development of an appropriately large cardiac output despite the Valsalva-like manoeuvre associated with the stroke, and the remarkable ability of the brain to maintain motor control and metabolism despite marked reductions in cerebral blood flow and oxygenation.

Rowing Injuries

Participation in the sport of rowing has been steadily increasing in recent decades, yet few studies address the specific injuries incurred. This article reviews the most common injuries described in the literature, including musculoskeletal problems in the lower back, ribs, shoulder, wrist and knee. A review of basic rowing physiology and equipment is included, along with a description of the mechanics of the rowing stroke. This information is necessary in order to make an accurate diagnosis and treatment protocol for these injuries, which are mainly chronic in nature. The most frequently injured region is the low back, mainly due to excessive hyperflexion and twisting, and can include specific injuries such as spondylolysis, sacroiliac joint dysfunction and disc herniation. Rib stress fractures account for the most time lost from on-water training and competition. Although theories abound for the mechanism of injury, the exact aetiology of rib stress fractures remains unknown. Other injuries discussed within, which are specific to ribs, include costochondritis, costovertebral joint subluxation and intercostal muscle strains. Shoulder pain is quite common in rowers and can be the result of overuse, poor technique, or tension in the upper body. Injuries concerning the forearm and wrist are also common, and can include exertional compartment syndrome, lateral epicondylitis, deQuervain's and intersection syndrome, and tenosynovitis of the wrist extensors. In the lower body, the major injuries reported include generalised patellofemoral pain due to abnormal patellar tracking, and iliotibial band friction syndrome. Lastly, dermatological issues, such as blisters and abrasions, and miscellaneous issues, such as environmental concerns and the female athlete triad, are also included in this article.Pathophysiology, mechanism of injury, assessment and management strategies are outlined in the text for each injury, with special attention given to ways to correct biomechanical or equipment problems specific to rowing. By gaining an understanding of basic rowing biomechanics and training habits, the physician and/or healthcare provider will be better equipped to treat and prevent injuries in the rowing population.

Lower heart rate response to ergometry rowing than to treadmill running in older men

For older people exercise intensity is often determined based on heart rate (HR) or the percentage of maximal HR (%HRmax). This study evaluated oxygen uptake (O2) and HR during ergometry rowing (combined arm and leg; sitting exercise) and treadmill running (leg; upright exercise) for 15 older people [age, (mean +/- SD) 62 +/- 3 years]. The HR was lower during ergometry rowing than during treadmill running at a blood lactate concentration of 4 mmol l-1 (151 +/- 4 beat min-1 versus 160 +/- 5 beat min-1, P<0.05) and at a maximal effort (171 +/- 7 beat min-1 versus 177 +/- 7 beat min-1, P<0.05). This was the case although the O2 was higher during ergometry rowing than during treamill running both at a blood lactate concentration of 4 mmol l-1 (3.0 +/- 0.4 l min-1 versus 2.7 +/- 0.4 l min-1, P<0.05) and at a maximal effort (3.4 +/- 0.4 l min-1 versus 3.1 +/- 0.3 l min-1, P<0.05]. %HRmax and %HR reserve were lower during ergometry rowing than during treadmill running. The results suggest that, in prescription of rowing for older people, the relation between HR and O2 for rowing and the attenuated HR response to rowing should be taken into consideration.

Effects of 16 weeks of resistance training on left ventricular morphology and systolic function in healthy men >60 years of age

Resistance training (RT) has gained popularity as an effective form of exercise for older adults. However, the effects of RT on left ventricular (LV) morphology and systolic function in older persons is not well known. The purpose of this study was to assess the effects of 16 weeks of RT on LV morphology and systolic function in healthy older men. Subjects were randomly assigned into a RT group (n = 10; mean+/- SD age, 68 +/- 3 years) or a nonexercise control group (n = 10; age 68 +/- 4 years). RT was performed 3 times per week for 16 weeks at a mean intensity between 60% and 80% of 1 repetition maximum. Leg and bench press 1 repetition maximum and 2-dimensional echocardiography were performed at baseline and after 4, 8, 12, and 16 weeks of training in the RT group. Sixteen weeks of RT was associated with an increase in leg press maximal strength (baseline, 285 +/- 48 kg; after 16 weeks, 367 +/- 47 kg; p <0.05) and bench press maximal strength (baseline, 59 +/- 11 kg; after 16 weeks, 69 +/- 11 kg; p <0.05). No change in leg press maximal strength (baseline, 291 +/- 59 kg; after 16 weeks, 290 +/- 53 kg; p >0.05) or bench press maximal strength (baseline, 60 +/- 9 kg; after 16 weeks, 61 +/- 13 kg; p > .05) was found in control subjects during the same time. RT was not associated with changes in LV cavity size, wall thickness, mass, or systolic function after 4, 8, 12, and 16 weeks of exercise. Thus, 16 weeks of RT was sufficient to increase leg press and bench press maximal strength but did not alter the size or systolic function of the senescent left ventricle.

Left ventricular morphology in junior and master resistance trained athletes

PURPOSE

The objective of this cross-sectional investigation was to assess the effects of short (< 5 yr) versus long-term (> or = 18 yr) resistance training (RT) on left ventricular (LV) dimensions and mass.

METHODS

The subjects for this study were 20 elite male powerlifters (8 junior athletes [JA], mean +/- SD, age: 21.1 +/- 1.2 yr and 12 master athletes [MA], age: 46.0 +/- 5.5 yr) and 19 age-matched male controls (8 young controls [YC], age: 21.8 +/- 2.8 yr and 11 middle-aged controls [MAC], age: 46.8 +/- 4.4 yr). Two-dimensionally guided transthoracic M-mode echocardiograms were performed at rest to quantify LV systolic and diastolic cavity dimension (LVIDs and LVIDd, respectively), ventricular septal wall thickness (VST), posterior wall thickness (PWT), LV mass (LVM), and LV systolic function as measured as fractional shortening (FS).

RESULTS

Short- or long-term RT was not associated with a significant alteration in LVIDd (JA: 53.2 +/- 4.5 mm, YC: 52.1 +/- 3.7 mm, MA: 53.0 +/- 5.1 mm, MAC: 51.8 +/- 4.4 mm), LVIDs (JA: 33.5 +/- 4.8 mm, YC: 32.9 +/- 3.4 mm, MA: 33.0 +/- 4.4 mm, MAC: 31.4 +/- 3.7 mm), VST (JA: 9.4 +/- 0.9 mm, YC: 9.4 +/- 0.9 mm, MA: 9.4 +/- 1.6 mm, MAC: 9.7 +/- 0.9 mm), PWT (JA: 9.2 +/- 0.9 mm, YC: 9.4 +/- 0.9 mm, MA: 9.0 +/- 1.1 mm, MAC: 9.5 +/- 1.0 mm), LVM (JA: 184.6 +/- 36.1 g, YC: 179.0 +/- 26.5 g, MA, 183.3 +/- 58.1 g, MAC: 184.1 +/- 38.1 g), or FS (JA: 0.37 +/- 0.1%, YC: 0.37 +/- 0.05%, MA: 0.38 +/- 0.1%, MAC: 0.40 +/- 0.04%).

CONCLUSIONS

These findings suggest that short or long-term RT as performed by elite junior and master powerlifters does not alter LV morphology or systolic function.

Middle cerebral artery blood velocity during exercise in patients with atrial fibrillation

Atrial fibrillation limits the ability to increase cardiac output during exercise and may, in turn, affect the exercise-associated elevation in cerebral perfusion. In nine patients with atrial fibrillation (AF) and in five age-matched healthy subjects, middle cerebral artery blood velocity (MCA Vmean) was measured during incremental exercise using the transcranial Doppler. The AF patient group exhibited a lower aerobic capacity than the control group [peak work rate: 106 W (71-153 W; median and range) vs. 129 W (118-1.9 W) and maximal oxygen uptake: 1.4 l min-1 (1.0-1.9 l min-1) vs. 1.7 l min-1 (1.4-2.2 l min-1); P = 0.05]. At rest, MCA Vmean was not significantly different between the two groups [43 cm s-1 (39-56 cm s-1) vs. 52 cm s-1 (40-68 cm s-1)]. During intense cycling, the increase in MCA Vmean was to 51 cm s-1 (40-78 cm s-1) (9%) in the AF group and lower than in the healthy subjects [to 62 cm s-1 (50-81 cm s-1) 23%; P < 0.05], which corresponded with the smaller than expected increase in cardiac output [156% (130-169%) vs. 180%]. Thus, there was a correlation between the increase in MCA Vmean and the ability to increase cardiac output (r2 = 0.55, P < 0.01). We suggest that, during exercise with a large muscle mass, atrial fibrillation affects the ability to elevate cerebral perfusion, and this results from an impaired ability to increase cardiac output.

Impact of different sports and training on cardiac structure and function

There is overwhelming evidence, particularly from echocardiography, that the heart of competitive athletes may differ from that of nonathletes, matched for age, gender, and body size. A larger left ventricular mass has been shown in athletes performing predominantly dynamic aerobic and anaerobic sports, in athletes engaged in static training, and in players of ball sports. Enlargement of the left ventricular internal diameter was most pronounced and reached about 10% in athletes performing predominantly dynamic sports; mainly strength training athletes had a lesser increase of the internal dimension, which was limited to 2.5%. Also the left ventricular wall appeared to be thickened in all types of athletes compared with controls. In sports with high dynamic and low static demands, wall thickness was proportionate or slightly disproportionate to the size of the internal diameter so that relative wall thickness was not different from controls or slightly increased (predominantly eccentric hypertrophy). In strength athletes, the disproportionate increase of wall thickness averaged about 12% (predominantly concentric hypertrophy). In sports with high dynamic and high static demands and requiring prolonged training, such as cycling, the increases of absolute and relative wall thickness reached 29% and 19% and were more pronounced than in runners (mixed hypertrophy). A plausible interpretation of these results is that the development of so-called eccentric or concentric left ventricular hypertrophy according to the type of sports cannot be regarded as an absolute or dichotomous concept because training regimens and sports activities are not exclusively dynamic or static and because the load on the heart is not purely of the volume or the pressure type. Most studies agree that left ventricular systolic and diastolic function is normal in the athlete at rest, whereas diastolic function seems to be enhanced in the exercising endurance athlete. The consistency of the results of studies on athletes in the competitive and the resting season, of training of sedentary subjects, and of spinal cord-injured patients suggests that variations in physical activity can alter left ventricular structure; genetic factors do not seem to be involved in the size of the left ventricular internal diameter but have to be taken into account to interpret wall thickness.