adapted swimming sports and rehabilitation

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ADAPTED SWIMMING SPORTS AND REHABILITATION
height, 178.3cm, (SD= 8.4), weight, 78.5kg (± 11.4), body
surface, 2.1m 2 (± 0.24). The test consisted of three 3 minute
swims at the same mean swimming speed with added, subtracted
or no extra load.
One S-VHS video camera was placed outside the flume perpendicular
to the swimming direction at 3.5-m from the swimmer.
The actual camera view in the swimming plane was 4-m
x 3-m. At the start of each video session a 1-m calibration
ruler was placed in both the vertical and horizontal direction
and recorded. Reference makers were set at eight points on
the left side of the body: toe, ankle, knee, hip, shoulder, elbow,
wrist and top middle finger. Recordings were made during
each step, in order to analyse 10 movement cycles in the middle
of each step. Sampling frequency was 50 Hz. Digitizing
was done using the SIMI-Motion “ software package 6.1 and
analysis was based on the breaststroke phase model of
Wiegand et al. (12) (Figure 1).
Figure 1. Breaststroke Phase-Model by Jähnig et al. (7).
To describe the complex movement, time-discrete (paths, durations,
velocities, angles) and time-continuous characteristics
(v x-t-progress of the hip depend on arm and leg by Federle
(4)), and timing of the swim-movement (Phase Structure
Quotient-PSQ of Blaser et al. (1)) were examined. All in all 57
movement-parameters were determined in 3 swimming situations
in each patient. Means and standard deviations were
determined. Significant changes of parameters over 10 movement
cycles between load steps were calculated using the nonparametric
Wilcoxon-test. The level of significance was set at P
< 0.05. A factor analysis (principle –component analysis) was
performed as described by Hotelling (6) and Kelly (7). Phase
structure quotient for both arm and leg movements were determined
as follows:
PSQ = (duration of main phase/ duration of initiation phase
+ duration of linking phase + duration of preparation phase)
x 100%(1).
RESULTS
Based on the time-discrete findings 9 parameters were found to
be relevant to describe the changes in swimming movement of
the CAD-patients examined. These 9 parameters showed a frequency
of change of more than 5 (Table 1). All in all only one
patient demonstrated no significant changes over the increasing
load steps. On average 31 (±14) parameters changed.
Rev Port Cien Desp 6(Supl.2) 351-357
Table 1. Frequency and Characteristic of time-discrete kinematic
parameters during swimming.
Frequency
Parameter ≥ 5 Characteristic
Vertical path of hand in main phase of arm 8 1 x s; 1 x f ; 5 x d (^);
1 x d (v)
Vertical path of foot in main phase of leg 7 2 x s; 1 x d (^); 4 x d (v)
Resultant path of hand in main phase of arm 6 2 x s; 2 x d (^); 2 x d (v)
Horizontal path of hand in main phase of arm 6 2 x s; 3 x d (^); 1 x d (v)
Horizontal path of hand during arm stroke 5 1 x s; 3 x d (^); 1 x d (v)
Horizontal path of hip during leg stroke 5 2 x f; 1 x d (^); 2 x d (v)
Duration of propulsion-pause between main
phase of arm and main phase of leg 8 2 x s; 2 x d (^); 4 x d (v)
Duration of propulsion-pause between main
phase of leg and main phase of arm 7 2 x f; 5 x d (^)
Angle of attack of hip-shoulder-water surface 5 1 x f; 4 x d (^)
Legend: s-increasing, f-decreasing, d-discontinuous (^)=direction
From the time-continuous point of view individual time series
patterns were observed in arm and leg movements. Figure 2
shows examples of an arm-swimmer (left) and leg-swimmer
(right). It was also possible to distinguish so called “changeswimmers”
(4) with differing propulsion of the arms and legs.
Only one patient actually demonstrated an ideal velocity-timeregime
of the hip according to Costill et al. (3) or Schramm
(10). In total a marked divergent regime in horizontal hipvelocity
was observed in this population: 12 arm-swimmers, 4
leg-swimmers and 10 change-swimmers.
The calculated PSQ describes some problems of these patients to
react to increased load conditions. Six patients showed significant
changes of PSQ of the arms. The other 20 patients did not
change time-continuous characteristics with increasing loads.
The calculated PSQ-values of the legs changed significantly in 10
patients whereas 16 patients showed no adaptation during the
step-test. As an example figure 3 shows the inter-individual
adaptation of the development of PSQ of the arms and legs.
Figure 2. Breaststroke arm-swimmer (left) and leg-swimmer (right).
Figure 3. Two examples of the development of PSQ of the arm (PSQ A)
and leg (PSQ B). Significant differences between load steps (*p ≤ .05,
**p ≤ .01) are indicated.